99970391 has 2 divisors, whose sum is σ = 99970392. Its totient is φ = 99970390.

The previous prime is 99970373. The next prime is 99970393. The reversal of 99970391 is 19307999.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99970391 is a prime.

Together with 99970393, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_5759849 and since 99970391 and 5759849 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99970393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49985195 + 49985196.

It is an arithmetic number, because the mean of its divisors is an integer number (49985196).

Almost surely, 2^99970391 is an apocalyptic number.

99970391 is a deficient number, since it is larger than the sum of its proper divisors (1).

99970391 is an equidigital number, since it uses as much as digits as its factorization.

99970391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 137781, while the sum is 47.

The square root of 99970391 is about 9998.5194403972. The cubic root of 99970391 is about 464.1130679046.

The spelling of 99970391 in words is "ninety-nine million, nine hundred seventy thousand, three hundred ninety-one".