671521564 has 24 divisors (see below), whose sum is σ = 1389356640. Its totient is φ = 277870656.

The previous prime is 671521561. The next prime is 671521577. The reversal of 671521564 is 465125176.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671521561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 412687 + ... + 414310.

It is an arithmetic number, because the mean of its divisors is an integer number (57889860).

Almost surely, 2^671521564 is an apocalyptic number.

It is an amenable number.

671521564 is an abundant number, since it is smaller than the sum of its proper divisors (717835076).

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

671521564 is a wasteful number, since it uses less digits than its factorization.

671521564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827037 (or 827035 counting only the distinct ones).

The product of its digits is 50400, while the sum is 37.

The square root of 671521564 is about 25913.7331158596. The cubic root of 671521564 is about 875.6959096169.

The spelling of 671521564 in words is "six hundred seventy-one million, five hundred twenty-one thousand, five hundred sixty-four".