This number is a prime.
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Largest known full auto-insertable of reversed primes such that it remains prime after all the possible internal auto-insertions of the reversed prime, one at a time. 5916623 generates 6 primes: 5'3266195'916623, 59'3266195'16623, 591'3266195'6623, 5916'3266195'623, 59166'3266195'23, 591662'3266195'3. [Rivera]