21945317031 has 24 divisors (see below), whose sum is σ = 34586072976. Its totient is φ = 13298048640.

The previous prime is 21945317011. The next prime is 21945317039. The reversal of 21945317031 is 13071354912.

21945317031 is a `hidden beast` number, since 2 + 1 + 9 + 453 + 170 + 31 = 666.

It is not a de Polignac number, because 21945317031 - 2⁷ = 21945316903 is a prime.

It is a super-2 number, since 2×21945317031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945317039) 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, 777441 + ... + 805173.

It is an arithmetic number, because the mean of its divisors is an integer number (1441086374).

Almost surely, 2^21945317031 is an apocalyptic number.

21945317031 is a deficient number, since it is larger than the sum of its proper divisors (12640755945).

21945317031 is a wasteful number, since it uses less digits than its factorization.

21945317031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35743 (or 35740 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The spelling of 21945317031 in words is "twenty-one billion, nine hundred forty-five million, three hundred seventeen thousand, thirty-one".