921672720 has 60 divisors (see below), whose sum is σ = 3095286636. Its totient is φ = 245779200.

The previous prime is 921672683. The next prime is 921672733. The reversal of 921672720 is 27276129.

It can be written as a sum of positive squares in 2 ways, for example, as 272646144 + 649026576 = 16512^2 + 25476^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 639331 + ... + 640770.

Almost surely, 2^921672720 is an apocalyptic number.

921672720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

921672720 is an abundant number, since it is smaller than the sum of its proper divisors (2173613916).

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

921672720 is a wasteful number, since it uses less digits than its factorization.

921672720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280120 (or 1280111 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 921672720 is about 30359.0632266544. The cubic root of 921672720 is about 973.1779145519.

The spelling of 921672720 in words is "nine hundred twenty-one million, six hundred seventy-two thousand, seven hundred twenty".