21660536601652 has 24 divisors (see below), whose sum is σ = 41817433705992. Its totient is φ = 9753337305600.

The previous prime is 21660536601631. The next prime is 21660536601653. The reversal of 21660536601652 is 25610663506612.

It can be written as a sum of positive squares in 4 ways, for example, as 20106256 + 21660516495396 = 4484^2 + 4654086^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21660536601596 and 21660536601605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660536601653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5079861049 + ... + 5079865312.

It is an arithmetic number, because the mean of its divisors is an integer number (1742393071083).

Almost surely, 2^{21660536601652} is an apocalyptic number.

It is an amenable number.

21660536601652 is a deficient number, since it is larger than the sum of its proper divisors (20156897104340).

21660536601652 is a wasteful number, since it uses less digits than its factorization.

21660536601652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10159726419 (or 10159726417 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 49.

The spelling of 21660536601652 in words is "twenty-one trillion, six hundred sixty billion, five hundred thirty-six million, six hundred one thousand, six hundred fifty-two".