645725660 has 48 divisors (see below), whose sum is σ = 1403523072. Its totient is φ = 249288000.

The previous prime is 645725653. The next prime is 645725693. The reversal of 645725660 is 66527546.

It is a congruent number.

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, 273485 + ... + 275835.

It is an arithmetic number, because the mean of its divisors is an integer number (29240064).

Almost surely, 2^645725660 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 645725660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (701761536).

645725660 is an abundant number, since it is smaller than the sum of its proper divisors (757797412).

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

645725660 is a wasteful number, since it uses less digits than its factorization.

645725660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2834 (or 2832 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 41.

The square root of 645725660 is about 25411.1325997091. The cubic root of 645725660 is about 864.3361585592.

The spelling of 645725660 in words is "six hundred forty-five million, seven hundred twenty-five thousand, six hundred sixty".