671991625 has 32 divisors (see below), whose sum is σ = 872894880. Its totient is φ = 515872000.

The previous prime is 671991613. The next prime is 671991629. The reversal of 671991625 is 526199176.

It can be written as a sum of positive squares in 16 ways, for example, as 216766729 + 455224896 = 14723^2 + 21336^2 .

It is not a de Polignac number, because 671991625 - 2²¹ = 669894473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (671991629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 713655 + ... + 714595.

It is an arithmetic number, because the mean of its divisors is an integer number (27277965).

Almost surely, 2^671991625 is an apocalyptic number.

It is an amenable number.

671991625 is a deficient number, since it is larger than the sum of its proper divisors (200903255).

671991625 is a wasteful number, since it uses less digits than its factorization.

671991625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182 (or 1172 counting only the distinct ones).

The product of its digits is 204120, while the sum is 46.

The square root of 671991625 is about 25922.8012568086. The cubic root of 671991625 is about 875.9001892251.

The spelling of 671991625 in words is "six hundred seventy-one million, nine hundred ninety-one thousand, six hundred twenty-five".