671379921 has 15 divisors (see below), whose sum is σ = 1003274041. Its totient is φ = 447431148.

The previous prime is 671379893. The next prime is 671379937. The reversal of 671379921 is 129973176.

The square root of 671379921 is 25911.

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

It is not a de Polignac number, because 671379921 - 2⁹ = 671379409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (671309921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 231760 + ... + 234638.

Almost surely, 2^671379921 is an apocalyptic number.

671379921 is the 25911-st square number.

671379921 is the 12956-th centered octagonal number.

It is an amenable number.

671379921 is a deficient number, since it is larger than the sum of its proper divisors (331894120).

671379921 is an frugal number, since it uses more digits than its factorization.

671379921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5770 (or 2882 counting only the distinct ones).

The product of its digits is 142884, while the sum is 45.

The cubic root of 671379921 is about 875.6343355616.

Multiplying 671379921 by its product of digits (142884), we get a square (95929448632164 = 9794358²).

The spelling of 671379921 in words is "six hundred seventy-one million, three hundred seventy-nine thousand, nine hundred twenty-one".