645511964 has 24 divisors (see below), whose sum is σ = 1197404208. Its totient is φ = 303438080.

The previous prime is 645511949. The next prime is 645511967. The reversal of 645511964 is 469115546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645511967) by changing a digit.

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, 64199 + ... + 73569.

It is an arithmetic number, because the mean of its divisors is an integer number (49891842).

Almost surely, 2^645511964 is an apocalyptic number.

It is an amenable number.

645511964 is a deficient number, since it is larger than the sum of its proper divisors (551892244).

645511964 is a wasteful number, since it uses less digits than its factorization.

645511964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10405 (or 10403 counting only the distinct ones).

The product of its digits is 129600, while the sum is 41.

The square root of 645511964 is about 25406.9274805121. The cubic root of 645511964 is about 864.2408004371.

The spelling of 645511964 in words is "six hundred forty-five million, five hundred eleven thousand, nine hundred sixty-four".