21173741864 has 32 divisors (see below), whose sum is σ = 43340918400. Its totient is φ = 9617541120.

The previous prime is 21173741821. The next prime is 21173741881. The reversal of 21173741864 is 46814737112.

It is a Harshad number since it is a multiple of its sum of digits (44).

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, 38609 + ... + 209375.

It is an arithmetic number, because the mean of its divisors is an integer number (1354403700).

Almost surely, 2^21173741864 is an apocalyptic number.

It is an amenable number.

21173741864 is an abundant number, since it is smaller than the sum of its proper divisors (22167176536).

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

21173741864 is a wasteful number, since it uses less digits than its factorization.

21173741864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172193 (or 172189 counting only the distinct ones).

The product of its digits is 225792, while the sum is 44.

The spelling of 21173741864 in words is "twenty-one billion, one hundred seventy-three million, seven hundred forty-one thousand, eight hundred sixty-four".