661427660 has 12 divisors (see below), whose sum is σ = 1388998128. Its totient is φ = 264571056.

The previous prime is 661427659. The next prime is 661427719. The reversal of 661427660 is 66724166.

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, 16535672 + ... + 16535711.

It is an arithmetic number, because the mean of its divisors is an integer number (115749844).

Almost surely, 2^661427660 is an apocalyptic number.

It is an amenable number.

661427660 is an abundant number, since it is smaller than the sum of its proper divisors (727570468).

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

661427660 is a wasteful number, since it uses less digits than its factorization.

661427660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33071392 (or 33071390 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 661427660 is about 25718.2359426147. The cubic root of 661427660 is about 871.2860971564.

The spelling of 661427660 in words is "six hundred sixty-one million, four hundred twenty-seven thousand, six hundred sixty".