21157636166 has 8 divisors (see below), whose sum is σ = 31851027120. Its totient is φ = 10540627128.

The previous prime is 21157636151. The next prime is 21157636211. The reversal of 21157636166 is 66163675112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

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, 19094786 + ... + 19095893.

It is an arithmetic number, because the mean of its divisors is an integer number (3981378390).

Almost surely, 2^21157636166 is an apocalyptic number.

21157636166 is a deficient number, since it is larger than the sum of its proper divisors (10693390954).

21157636166 is a wasteful number, since it uses less digits than its factorization.

21157636166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38190958.

The product of its digits is 272160, while the sum is 44.

It can be divided in two parts, 211576 and 36166, that added together give a palindrome (247742).

The spelling of 21157636166 in words is "twenty-one billion, one hundred fifty-seven million, six hundred thirty-six thousand, one hundred sixty-six".