21660259328 has 44 divisors (see below), whose sum is σ = 44355534132. Its totient is φ = 10565959680.

The previous prime is 21660259319. The next prime is 21660259363. The reversal of 21660259328 is 82395206612.

It can be written as a sum of positive squares in 2 ways, for example, as 5202448384 + 16457810944 = 72128^2 + 128288^2 .

It is a super-2 number, since 2×21660259328² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215975 + ... + 299942.

Almost surely, 2^21660259328 is an apocalyptic number.

It is an amenable number.

21660259328 is an abundant number, since it is smaller than the sum of its proper divisors (22695274804).

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

21660259328 is an equidigital number, since it uses as much as digits as its factorization.

21660259328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515978 (or 515960 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The spelling of 21660259328 in words is "twenty-one billion, six hundred sixty million, two hundred fifty-nine thousand, three hundred twenty-eight".