99921897 has 24 divisors (see below), whose sum is σ = 153001440. Its totient is φ = 64449000.

The previous prime is 99921883. The next prime is 99921911. The reversal of 99921897 is 79812999.

It is an interprime number because it is at equal distance from previous prime (99921883) and next prime (99921911).

It is not a de Polignac number, because 99921897 - 2⁴ = 99921881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99921847) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24022 + ... + 27872.

It is an arithmetic number, because the mean of its divisors is an integer number (6375060).

Almost surely, 2^99921897 is an apocalyptic number.

It is an amenable number.

99921897 is a deficient number, since it is larger than the sum of its proper divisors (53079543).

99921897 is a wasteful number, since it uses less digits than its factorization.

99921897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3922 (or 3885 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 99921897 is about 9996.0940871923. The cubic root of 99921897 is about 464.0380112167.

The spelling of 99921897 in words is "ninety-nine million, nine hundred twenty-one thousand, eight hundred ninety-seven".