68640172 has 12 divisors (see below), whose sum is σ = 120815856. Its totient is φ = 34121360.

The previous prime is 68640157. The next prime is 68640193. The reversal of 68640172 is 27104686.

It is a super-2 number, since 2×68640172² = 9422946424379168, which contains 22 as substring.

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, 48904 + ... + 50287.

It is an arithmetic number, because the mean of its divisors is an integer number (10067988).

Almost surely, 2^68640172 is an apocalyptic number.

It is an amenable number.

68640172 is a deficient number, since it is larger than the sum of its proper divisors (52175684).

68640172 is a wasteful number, since it uses less digits than its factorization.

68640172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99368 (or 99366 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 68640172 is about 8284.9364511745. The cubic root of 68640172 is about 409.4423749955.

The spelling of 68640172 in words is "sixty-eight million, six hundred forty thousand, one hundred seventy-two".