661565160 has 48 divisors (see below), whose sum is σ = 2150087940. Its totient is φ = 176417280.

The previous prime is 661565153. The next prime is 661565173. The reversal of 661565160 is 61565166.

It can be written as a sum of positive squares in 2 ways, for example, as 650556036 + 11009124 = 25506^2 + 3318^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 918481 + ... + 919200.

Almost surely, 2^661565160 is an apocalyptic number.

661565160 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661565160 is an abundant number, since it is smaller than the sum of its proper divisors (1488522780).

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

661565160 is a wasteful number, since it uses less digits than its factorization.

661565160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1837698 (or 1837691 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 661565160 is about 25720.9090041546. The cubic root of 661565160 is about 871.3464683529.

The spelling of 661565160 in words is "six hundred sixty-one million, five hundred sixty-five thousand, one hundred sixty".