21689323965 has 32 divisors (see below), whose sum is σ = 39600936960. Its totient is φ = 11254997952.

The previous prime is 21689323963. The next prime is 21689323991. The reversal of 21689323965 is 56932398612.

21689323965 is a `hidden beast` number, since 2 + 168 + 93 + 2 + 396 + 5 = 666.

It is not a de Polignac number, because 21689323965 - 2¹ = 21689323963 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21689323961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2166109 + ... + 2176098.

It is an arithmetic number, because the mean of its divisors is an integer number (1237529280).

Almost surely, 2^21689323965 is an apocalyptic number.

It is an amenable number.

21689323965 is a deficient number, since it is larger than the sum of its proper divisors (17911612995).

21689323965 is a wasteful number, since it uses less digits than its factorization.

21689323965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4342258 (or 4342252 counting only the distinct ones).

The product of its digits is 4199040, while the sum is 54.

It can be divided in two parts, 21 and 689323965, that added together give a palindrome (689323986).

The spelling of 21689323965 in words is "twenty-one billion, six hundred eighty-nine million, three hundred twenty-three thousand, nine hundred sixty-five".