66865560 has 64 divisors (see below), whose sum is σ = 211161600. Its totient is φ = 16891776.

The previous prime is 66865553. The next prime is 66865583. The reversal of 66865560 is 6556866.

It is a super-2 number, since 2×66865560² = 8942006228227200, which contains 22 as substring.

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, 12384 + ... + 16943.

It is an arithmetic number, because the mean of its divisors is an integer number (3299400).

Almost surely, 2^66865560 is an apocalyptic number.

66865560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66865560 is an abundant number, since it is smaller than the sum of its proper divisors (144296040).

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

66865560 is a wasteful number, since it uses less digits than its factorization.

66865560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29360 (or 29356 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 42.

The square root of 66865560 is about 8177.1364180867. The cubic root of 66865560 is about 405.8829691726.

It can be divided in two parts, 6686 and 5560, that added together give a triangular number (12246 = T₁₅₆).

The spelling of 66865560 in words is "sixty-six million, eight hundred sixty-five thousand, five hundred sixty".