99775891 has 2 divisors, whose sum is σ = 99775892. Its totient is φ = 99775890.

The previous prime is 99775883. The next prime is 99775901. The reversal of 99775891 is 19857799.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99775891 - 2³ = 99775883 is a prime.

It is not a weakly prime, because it can be changed into another prime (99775831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49887945 + 49887946.

It is an arithmetic number, because the mean of its divisors is an integer number (49887946).

Almost surely, 2^99775891 is an apocalyptic number.

99775891 is a deficient number, since it is larger than the sum of its proper divisors (1).

99775891 is an equidigital number, since it uses as much as digits as its factorization.

99775891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1428840, while the sum is 55.

The square root of 99775891 is about 9988.7882648497. The cubic root of 99775891 is about 463.8118834020.

The spelling of 99775891 in words is "ninety-nine million, seven hundred seventy-five thousand, eight hundred ninety-one".