660561156 has 30 divisors (see below), whose sum is σ = 1726838190. Its totient is φ = 220186944.

The previous prime is 660561149. The next prime is 660561157. The reversal of 660561156 is 651165066.

It can be written as a sum of positive squares in only one way, i.e., 624200256 + 36360900 = 24984^2 + 6030^2 .

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 660561156.

It is not an unprimeable number, because it can be changed into a prime (660561157) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1019061 + ... + 1019708.

It is an arithmetic number, because the mean of its divisors is an integer number (57561273).

Almost surely, 2^660561156 is an apocalyptic number.

It is an amenable number.

660561156 is an abundant number, since it is smaller than the sum of its proper divisors (1066277034).

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

660561156 is a wasteful number, since it uses less digits than its factorization.

660561156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2038785 (or 2038774 counting only the distinct ones).

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

The square root of 660561156 is about 25701.3843206937. The cubic root of 660561156 is about 870.9054544656.

The spelling of 660561156 in words is "six hundred sixty million, five hundred sixty-one thousand, one hundred fifty-six".