99891917 has 2 divisors, whose sum is σ = 99891918. Its totient is φ = 99891916.

The previous prime is 99891901. The next prime is 99891919. The reversal of 99891917 is 71919899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99880036 + 11881 = 9994^2 + 109^2 .

It is a cyclic number.

It is not a de Polignac number, because 99891917 - 2⁴ = 99891901 is a prime.

Together with 99891919, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99891919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49945958 + 49945959.

It is an arithmetic number, because the mean of its divisors is an integer number (49945959).

Almost surely, 2^99891917 is an apocalyptic number.

It is an amenable number.

99891917 is a deficient number, since it is larger than the sum of its proper divisors (1).

99891917 is an equidigital number, since it uses as much as digits as its factorization.

99891917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 53.

The square root of 99891917 is about 9994.5943889685. The cubic root of 99891917 is about 463.9915974623.

The spelling of 99891917 in words is "ninety-nine million, eight hundred ninety-one thousand, nine hundred seventeen".