645942544 has 80 divisors (see below), whose sum is σ = 1438796800. Its totient is φ = 278443008.

The previous prime is 645942541. The next prime is 645942569. The reversal of 645942544 is 445249546.

It is a self number, because there is not a number n which added to its sum of digits gives 645942544.

It is not an unprimeable number, because it can be changed into a prime (645942541) 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, 287377 + ... + 289615.

It is an arithmetic number, because the mean of its divisors is an integer number (17984960).

Almost surely, 2^645942544 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 645942544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (719398400).

645942544 is an abundant number, since it is smaller than the sum of its proper divisors (792854256).

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

645942544 is a wasteful number, since it uses less digits than its factorization.

645942544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2352 (or 2346 counting only the distinct ones).

The product of its digits is 691200, while the sum is 43.

The square root of 645942544 is about 25415.3997411019. The cubic root of 645942544 is about 864.4329177615.

The spelling of 645942544 in words is "six hundred forty-five million, nine hundred forty-two thousand, five hundred forty-four".