645332664 has 64 divisors (see below), whose sum is σ = 1670919840. Its totient is φ = 207567360.

The previous prime is 645332617. The next prime is 645332671. The reversal of 645332664 is 466233546.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73434 + ... + 81750.

Almost surely, 2^645332664 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 645332664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (835459920).

645332664 is an abundant number, since it is smaller than the sum of its proper divisors (1025587176).

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

645332664 is a wasteful number, since it uses less digits than its factorization.

645332664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8440 (or 8436 counting only the distinct ones).

The product of its digits is 311040, while the sum is 39.

The square root of 645332664 is about 25403.3986702567. The cubic root of 645332664 is about 864.1607746934.

The spelling of 645332664 in words is "six hundred forty-five million, three hundred thirty-two thousand, six hundred sixty-four".