99564323021 has 2 divisors, whose sum is σ = 99564323022. Its totient is φ = 99564323020.

The previous prime is 99564322999. The next prime is 99564323059. The reversal of 99564323021 is 12032346599.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98885720521 + 678602500 = 314461^2 + 26050^2 .

It is a cyclic number.

It is not a de Polignac number, because 99564323021 - 2³⁰ = 98490581197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99564323321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49782161510 + 49782161511.

It is an arithmetic number, because the mean of its divisors is an integer number (49782161511).

Almost surely, 2^99564323021 is an apocalyptic number.

It is an amenable number.

99564323021 is a deficient number, since it is larger than the sum of its proper divisors (1).

99564323021 is an equidigital number, since it uses as much as digits as its factorization.

99564323021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 349920, while the sum is 44.

The spelling of 99564323021 in words is "ninety-nine billion, five hundred sixty-four million, three hundred twenty-three thousand, twenty-one".