661371872 has 24 divisors (see below), whose sum is σ = 1488087216. Its totient is φ = 283444992.

The previous prime is 661371857. The next prime is 661371881. The reversal of 661371872 is 278173166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1476053 + ... + 1476500.

It is an arithmetic number, because the mean of its divisors is an integer number (62003634).

Almost surely, 2^661371872 is an apocalyptic number.

It is an amenable number.

661371872 is an abundant number, since it is smaller than the sum of its proper divisors (826715344).

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

661371872 is a wasteful number, since it uses less digits than its factorization.

661371872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2952570 (or 2952562 counting only the distinct ones).

The product of its digits is 84672, while the sum is 41.

The square root of 661371872 is about 25717.1513196932. The cubic root of 661371872 is about 871.2616003099.

The spelling of 661371872 in words is "six hundred sixty-one million, three hundred seventy-one thousand, eight hundred seventy-two".