645929904 has 80 divisors (see below), whose sum is σ = 1699391232. Its totient is φ = 211378944.

The previous prime is 645929899. The next prime is 645929941. The reversal of 645929904 is 409929546.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 784437 + ... + 785259.

Almost surely, 2^645929904 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 645929904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (849695616).

645929904 is an abundant number, since it is smaller than the sum of its proper divisors (1053461328).

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

645929904 is a wasteful number, since it uses less digits than its factorization.

645929904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1114 (or 1108 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 48.

The square root of 645929904 is about 25415.1510717525. The cubic root of 645929904 is about 864.4272792294.

It can be divided in two parts, 6459 and 29904, that added together give a palindrome (36363).

The spelling of 645929904 in words is "six hundred forty-five million, nine hundred twenty-nine thousand, nine hundred four".