21764599864 has 32 divisors (see below), whose sum is σ = 49093084800. Its totient is φ = 8836754400.

The previous prime is 21764599861. The next prime is 21764599933. The reversal of 21764599864 is 46899546712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764599861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10226662 + ... + 10228789.

It is an arithmetic number, because the mean of its divisors is an integer number (1534158900).

Almost surely, 2^21764599864 is an apocalyptic number.

It is an amenable number.

21764599864 is an abundant number, since it is smaller than the sum of its proper divisors (27328484936).

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

21764599864 is a wasteful number, since it uses less digits than its factorization.

21764599864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20455483 (or 20455479 counting only the distinct ones).

The product of its digits is 26127360, while the sum is 61.

The spelling of 21764599864 in words is "twenty-one billion, seven hundred sixty-four million, five hundred ninety-nine thousand, eight hundred sixty-four".