672664065921 has 15 divisors (see below), whose sum is σ = 1004854878291. Its totient is φ = 448437789648.

The previous prime is 672664065877. The next prime is 672664065943. The reversal of 672664065921 is 129560466276.

The square root of 672664065921 is 820161.

It is a perfect power (a square), and thus also a powerful number.

672664065921 is a `hidden beast` number, since 6 + 7 + 2 + 6 + 6 + 40 + 6 + 592 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 314677243521 + 357986822400 = 560961^2 + 598320^2 .

It is not a de Polignac number, because 672664065921 - 2²⁵ = 672630511489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (672664065991) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 7335885 + ... + 7427013.

Almost surely, 2^672664065921 is an apocalyptic number.

672664065921 is the 820161-st square number.

672664065921 is the 410081-st centered octagonal number.

It is an amenable number.

672664065921 is a deficient number, since it is larger than the sum of its proper divisors (332190812370).

672664065921 is an frugal number, since it uses more digits than its factorization.

672664065921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182270 (or 91132 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 54.

The spelling of 672664065921 in words is "six hundred seventy-two billion, six hundred sixty-four million, sixty-five thousand, nine hundred twenty-one".