21600651864 has 48 divisors (see below), whose sum is σ = 59357171160. Its totient is φ = 6545651200.

The previous prime is 21600651859. The next prime is 21600651881. The reversal of 21600651864 is 46815600612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3716217 + ... + 3722024.

Almost surely, 2^21600651864 is an apocalyptic number.

21600651864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21600651864 is an abundant number, since it is smaller than the sum of its proper divisors (37756519296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21600651864 is a wasteful number, since it uses less digits than its factorization.

21600651864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7438272 (or 7438257 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 39.

The spelling of 21600651864 in words is "twenty-one billion, six hundred million, six hundred fifty-one thousand, eight hundred sixty-four".