645509508 has 48 divisors (see below), whose sum is σ = 1744955520. Its totient is φ = 181903104.

The previous prime is 645509471. The next prime is 645509519. The reversal of 645509508 is 805905546.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 645509508.

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, 46503 + ... + 58766.

It is an arithmetic number, because the mean of its divisors is an integer number (36353240).

Almost surely, 2^645509508 is an apocalyptic number.

It is an amenable number.

645509508 is an abundant number, since it is smaller than the sum of its proper divisors (1099446012).

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

645509508 is a wasteful number, since it uses less digits than its factorization.

645509508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105356 (or 105354 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 42.

The square root of 645509508 is about 25406.8791471916. The cubic root of 645509508 is about 864.2397043675.

The spelling of 645509508 in words is "six hundred forty-five million, five hundred nine thousand, five hundred eight".