645671572 has 24 divisors (see below), whose sum is σ = 1390678016. Its totient is φ = 255430368.

The previous prime is 645671561. The next prime is 645671581. The reversal of 645671572 is 275176546.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 886548 + ... + 887275.

Almost surely, 2^645671572 is an apocalyptic number.

It is an amenable number.

645671572 is an abundant number, since it is smaller than the sum of its proper divisors (745006444).

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

645671572 is a wasteful number, since it uses less digits than its factorization.

645671572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1773847 (or 1773845 counting only the distinct ones).

The product of its digits is 352800, while the sum is 43.

The square root of 645671572 is about 25410.0683194674. The cubic root of 645671572 is about 864.3120247190.

The spelling of 645671572 in words is "six hundred forty-five million, six hundred seventy-one thousand, five hundred seventy-two".