66561156 has 24 divisors (see below), whose sum is σ = 172566240. Its totient is φ = 22187016.

The previous prime is 66561133. The next prime is 66561197. The reversal of 66561156 is 65116566.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a self number, because there is not a number n which added to its sum of digits gives 66561156.

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, 308046 + ... + 308261.

It is an arithmetic number, because the mean of its divisors is an integer number (7190260).

Almost surely, 2^66561156 is an apocalyptic number.

It is an amenable number.

66561156 is an abundant number, since it is smaller than the sum of its proper divisors (106005084).

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

66561156 is a wasteful number, since it uses less digits than its factorization.

66561156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616320 (or 616312 counting only the distinct ones).

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

The square root of 66561156 is about 8158.5020683947. The cubic root of 66561156 is about 405.2661076929.

The spelling of 66561156 in words is "sixty-six million, five hundred sixty-one thousand, one hundred fifty-six".