661564000 has 48 divisors (see below), whose sum is σ = 1625472576. Its totient is φ = 264624000.

The previous prime is 661563997. The next prime is 661564067. The reversal of 661564000 is 465166.

661564000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 661564000.

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, 78696 + ... + 86695.

It is an arithmetic number, because the mean of its divisors is an integer number (33864012).

Almost surely, 2^661564000 is an apocalyptic number.

It is an amenable number.

661564000 is an abundant number, since it is smaller than the sum of its proper divisors (963908576).

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

661564000 is a wasteful number, since it uses less digits than its factorization.

661564000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165416 (or 165398 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 661564000 is about 25720.8864543973. The cubic root of 661564000 is about 871.3459590745.

The spelling of 661564000 in words is "six hundred sixty-one million, five hundred sixty-four thousand".