661974642 has 24 divisors (see below), whose sum is σ = 1639175616. Its totient is φ = 189135576.

The previous prime is 661974617. The next prime is 661974683. The reversal of 661974642 is 246479166.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2626758 + ... + 2627009.

It is an arithmetic number, because the mean of its divisors is an integer number (68298984).

Almost surely, 2^661974642 is an apocalyptic number.

661974642 is an abundant number, since it is smaller than the sum of its proper divisors (977200974).

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

661974642 is a wasteful number, since it uses less digits than its factorization.

661974642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5253782 (or 5253779 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 661974642 is about 25728.8678724891. The cubic root of 661974642 is about 871.5262073145.

The spelling of 661974642 in words is "six hundred sixty-one million, nine hundred seventy-four thousand, six hundred forty-two".