672709995721 has 9 divisors (see below), whose sum is σ = 679389888429. Its totient is φ = 666095171436.

The previous prime is 672709995719. The next prime is 672709995761. The reversal of 672709995721 is 127599907276.

The square root of 672709995721 is 820189.

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

It is not a de Polignac number, because 672709995721 - 2¹ = 672709995719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (672709995701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 84475486 + ... + 84483448.

It is an arithmetic number, because the mean of its divisors is an integer number (75487765381).

Almost surely, 2^672709995721 is an apocalyptic number.

672709995721 is the 820189-th square number.

672709995721 is the 410095-th centered octagonal number.

It is an amenable number.

672709995721 is a deficient number, since it is larger than the sum of its proper divisors (6679892708).

672709995721 is an frugal number, since it uses more digits than its factorization.

672709995721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16132 (or 8066 counting only the distinct ones).

The product of its (nonzero) digits is 30005640, while the sum is 64.

Multiplying 672709995721 by its sum of digits (64), we get a square (43053439726144 = 6561512²).

The spelling of 672709995721 in words is "six hundred seventy-two billion, seven hundred nine million, nine hundred ninety-five thousand, seven hundred twenty-one".