645156 has 18 divisors (see below), whose sum is σ = 1630902. Its totient is φ = 215040.

The previous prime is 645149. The next prime is 645179. The reversal of 645156 is 651546.

It is a happy number.

645156 is a `hidden beast` number, since 645 + 15 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 360000 + 285156 = 600^2 + 534^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8925 + ... + 8996.

2⁶⁴⁵¹⁵⁶ is an apocalyptic number.

It is an amenable number.

645156 is an abundant number, since it is smaller than the sum of its proper divisors (985746).

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

645156 is a wasteful number, since it uses less digits than its factorization.

645156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17931 (or 17926 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 645156 is about 803.2160356965. The cubic root of 645156 is about 86.4081910959.

The spelling of 645156 in words is "six hundred forty-five thousand, one hundred fifty-six".