21252541631666 has 16 divisors (see below), whose sum is σ = 32908873701120. Its totient is φ = 10282952741040.

The previous prime is 21252541631653. The next prime is 21252541631707. The reversal of 21252541631666 is 66613614525212.

It is a super-2 number, since 2×21252541631666² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7716776 + ... + 10102163.

It is an arithmetic number, because the mean of its divisors is an integer number (2056804606320).

Almost surely, 2^{21252541631666} is an apocalyptic number.

21252541631666 is a deficient number, since it is larger than the sum of its proper divisors (11656332069454).

21252541631666 is a wasteful number, since it uses less digits than its factorization.

21252541631666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17838209.

The product of its digits is 3110400, while the sum is 50.

The spelling of 21252541631666 in words is "twenty-one trillion, two hundred fifty-two billion, five hundred forty-one million, six hundred thirty-one thousand, six hundred sixty-six".