21173157636 has 24 divisors (see below), whose sum is σ = 51107622720. Its totient is φ = 6814349472.

The previous prime is 21173157613. The next prime is 21173157659. The reversal of 21173157636 is 63675137112.

It is an interprime number because it is at equal distance from previous prime (21173157613) and next prime (21173157659).

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, 30420856 + ... + 30421551.

It is an arithmetic number, because the mean of its divisors is an integer number (2129484280).

Almost surely, 2^21173157636 is an apocalyptic number.

It is an amenable number.

21173157636 is an abundant number, since it is smaller than the sum of its proper divisors (29934465084).

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

21173157636 is a wasteful number, since it uses less digits than its factorization.

21173157636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60842443 (or 60842441 counting only the distinct ones).

The product of its digits is 158760, while the sum is 42.

The spelling of 21173157636 in words is "twenty-one billion, one hundred seventy-three million, one hundred fifty-seven thousand, six hundred thirty-six".