661365320 has 64 divisors (see below), whose sum is σ = 1855267200. Its totient is φ = 206138880.

The previous prime is 661365317. The next prime is 661365337. The reversal of 661365320 is 23563166.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104285 + ... + 110444.

It is an arithmetic number, because the mean of its divisors is an integer number (28988550).

Almost surely, 2^661365320 is an apocalyptic number.

It is an amenable number.

661365320 is an abundant number, since it is smaller than the sum of its proper divisors (1193901880).

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

661365320 is a wasteful number, since it uses less digits than its factorization.

661365320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214758 (or 214754 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 661365320 is about 25717.0239335737. The cubic root of 661365320 is about 871.2587231969.

The spelling of 661365320 in words is "six hundred sixty-one million, three hundred sixty-five thousand, three hundred twenty".