645708408 has 32 divisors (see below), whose sum is σ = 1620983760. Its totient is φ = 214341120.

The previous prime is 645708391. The next prime is 645708421. The reversal of 645708408 is 804807546.

It is a self number, because there is not a number n which added to its sum of digits gives 645708408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50035 + ... + 61602.

Almost surely, 2^645708408 is an apocalyptic number.

It is an amenable number.

645708408 is an abundant number, since it is smaller than the sum of its proper divisors (975275352).

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

645708408 is a wasteful number, since it uses less digits than its factorization.

645708408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111887 (or 111883 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 42.

The square root of 645708408 is about 25410.7931399238. The cubic root of 645708408 is about 864.3284609351.

The spelling of 645708408 in words is "six hundred forty-five million, seven hundred eight thousand, four hundred eight".