645405124 has 48 divisors (see below), whose sum is σ = 1397458048. Its totient is φ = 253974528.

The previous prime is 645405113. The next prime is 645405157. The reversal of 645405124 is 421504546.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65659 + ... + 74845.

Almost surely, 2^645405124 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 645405124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (698729024).

645405124 is an abundant number, since it is smaller than the sum of its proper divisors (752052924).

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

645405124 is a wasteful number, since it uses less digits than its factorization.

645405124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9404 (or 9402 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 31.

The square root of 645405124 is about 25404.8248173452. The cubic root of 645405124 is about 864.1931170545.

It can be divided in two parts, 645 and 405124, that added together give a square (405769 = 637²).

The spelling of 645405124 in words is "six hundred forty-five million, four hundred five thousand, one hundred twenty-four".