99910021 has 4 divisors (see below), whose sum is σ = 100358272. Its totient is φ = 99461772.

The previous prime is 99910007. The next prime is 99910039. The reversal of 99910021 is 12001999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 99910021 - 2¹⁷ = 99778949 is a prime.

It is the 9996-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99910001) by changing a digit.

It is a nontrivial repunit in base 9995.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223791 + ... + 224236.

It is an arithmetic number, because the mean of its divisors is an integer number (25089568).

Almost surely, 2^99910021 is an apocalyptic number.

It is an amenable number.

99910021 is a deficient number, since it is larger than the sum of its proper divisors (448251).

99910021 is a wasteful number, since it uses less digits than its factorization.

99910021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448250.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 99910021 is about 9995.5000375169. The cubic root of 99910021 is about 464.0196264117.

The spelling of 99910021 in words is "ninety-nine million, nine hundred ten thousand, twenty-one".