645612 has 48 divisors (see below), whose sum is σ = 1690752. Its totient is φ = 190080.

The previous prime is 645611. The next prime is 645629. The reversal of 645612 is 216546.

It is not an unprimeable number, because it can be changed into a prime (645611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8808 + ... + 8880.

It is an arithmetic number, because the mean of its divisors is an integer number (35224).

2⁶⁴⁵⁶¹² is an apocalyptic number.

It is a pronic number, being equal to 803×804.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (845376).

645612 is an abundant number, since it is smaller than the sum of its proper divisors (1045140).

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

645612 is a wasteful number, since it uses less digits than its factorization.

645612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 156 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 645612 is about 803.4998444306. The cubic root of 645612 is about 86.4285442381.

The spelling of 645612 in words is "six hundred forty-five thousand, six hundred twelve".