645813564 has 24 divisors (see below), whose sum is σ = 1643889408. Its totient is φ = 195701040.

The previous prime is 645813559. The next prime is 645813583. The reversal of 645813564 is 465318546.

It is a congruent number.

It is an unprimeable number.

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, 2446132 + ... + 2446395.

It is an arithmetic number, because the mean of its divisors is an integer number (68495392).

Almost surely, 2^645813564 is an apocalyptic number.

It is an amenable number.

645813564 is an abundant number, since it is smaller than the sum of its proper divisors (998075844).

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

645813564 is a wasteful number, since it uses less digits than its factorization.

645813564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4892545 (or 4892543 counting only the distinct ones).

The product of its digits is 345600, while the sum is 42.

The square root of 645813564 is about 25412.8621764649. The cubic root of 645813564 is about 864.3753780827.

The spelling of 645813564 in words is "six hundred forty-five million, eight hundred thirteen thousand, five hundred sixty-four".