21631368897 has 24 divisors (see below), whose sum is σ = 32425585920. Its totient is φ = 14410658160.

The previous prime is 21631368851. The next prime is 21631368911. The reversal of 21631368897 is 79886313612.

It is not a de Polignac number, because 21631368897 - 2¹² = 21631364801 is a prime.

It is a super-2 number, since 2×21631368897² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21631368097) 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, 318747 + ... + 380607.

It is an arithmetic number, because the mean of its divisors is an integer number (1351066080).

Almost surely, 2^21631368897 is an apocalyptic number.

21631368897 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21631368897 is a deficient number, since it is larger than the sum of its proper divisors (10794217023).

21631368897 is an equidigital number, since it uses as much as digits as its factorization.

21631368897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63315 (or 63303 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 21631368897 in words is "twenty-one billion, six hundred thirty-one million, three hundred sixty-eight thousand, eight hundred ninety-seven".