645516 has 48 divisors (see below), whose sum is σ = 1724800. Its totient is φ = 208656.

The previous prime is 645503. The next prime is 645521. The reversal of 645516 is 615546.

It is a happy number.

645516 is a `hidden beast` number, since 645 + 5 + 16 = 666.

645516 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 645516.

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, 4575 + ... + 4713.

2⁶⁴⁵⁵¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (862400).

645516 is an abundant number, since it is smaller than the sum of its proper divisors (1079284).

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

645516 is a wasteful number, since it uses less digits than its factorization.

645516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195 (or 187 counting only the distinct ones).

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

The square root of 645516 is about 803.4401035547. The cubic root of 645516 is about 86.4242601627.

The spelling of 645516 in words is "six hundred forty-five thousand, five hundred sixteen".