21992031 has 24 divisors (see below), whose sum is σ = 32904144. Its totient is φ = 14144640.

The previous prime is 21992027. The next prime is 21992039. The reversal of 21992031 is 13029912.

It is not a de Polignac number, because 21992031 - 2² = 21992027 is a prime.

It is a super-2 number, since 2×21992031² = 967298855009922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21991986 and 21992004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992039) 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, 39205 + ... + 39761.

It is an arithmetic number, because the mean of its divisors is an integer number (1371006).

Almost surely, 2^21992031 is an apocalyptic number.

21992031 is a deficient number, since it is larger than the sum of its proper divisors (10912113).

21992031 is a wasteful number, since it uses less digits than its factorization.

21992031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 21992031 is about 4689.5661846273. The cubic root of 21992031 is about 280.1700964775.

The spelling of 21992031 in words is "twenty-one million, nine hundred ninety-two thousand, thirty-one".