21764905216 has 36 divisors (see below), whose sum is σ = 43460306764. Its totient is φ = 10878566400.

The previous prime is 21764905193. The next prime is 21764905247. The reversal of 21764905216 is 61250946712.

It can be written as a sum of positive squares in 2 ways, for example, as 10630434816 + 11134470400 = 103104^2 + 105520^2 .

It is a super-2 number, since 2×21764905216² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 785356 + ... + 812596.

Almost surely, 2^21764905216 is an apocalyptic number.

It is an amenable number.

21764905216 is a deficient number, since it is larger than the sum of its proper divisors (21695401548).

21764905216 is an equidigital number, since it uses as much as digits as its factorization.

21764905216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30378 (or 30364 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 43.

The spelling of 21764905216 in words is "twenty-one billion, seven hundred sixty-four million, nine hundred five thousand, two hundred sixteen".