645909504 has 44 divisors (see below), whose sum is σ = 1721592504. Its totient is φ = 215302144.

The previous prime is 645909499. The next prime is 645909527. The reversal of 645909504 is 405909546.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102057 + ... + 108200.

Almost surely, 2^645909504 is an apocalyptic number.

645909504 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

645909504 is an abundant number, since it is smaller than the sum of its proper divisors (1075683000).

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

645909504 is a wasteful number, since it uses less digits than its factorization.

645909504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210280 (or 210262 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 645909504 is about 25414.7497331766. The cubic root of 645909504 is about 864.4181789117.

Adding to 645909504 its sum of digits (42), we get a palindrome (645909546).

The spelling of 645909504 in words is "six hundred forty-five million, nine hundred nine thousand, five hundred four".