661557360 has 80 divisors (see below), whose sum is σ = 2117007360. Its totient is φ = 170722560.

The previous prime is 661557359. The next prime is 661557389. The reversal of 661557360 is 63755166.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

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, 37020 + ... + 51899.

It is an arithmetic number, because the mean of its divisors is an integer number (26462592).

Almost surely, 2^661557360 is an apocalyptic number.

661557360 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661557360 is an abundant number, since it is smaller than the sum of its proper divisors (1455450000).

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

661557360 is a wasteful number, since it uses less digits than its factorization.

661557360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88966 (or 88960 counting only the distinct ones).

The product of its (nonzero) digits is 113400, while the sum is 39.

The square root of 661557360 is about 25720.7573760961. The cubic root of 661557360 is about 871.3430438834.

The spelling of 661557360 in words is "six hundred sixty-one million, five hundred fifty-seven thousand, three hundred sixty".