646399584 has 72 divisors (see below), whose sum is σ = 1841570640. Its totient is φ = 215071488.

The previous prime is 646399573. The next prime is 646399591. The reversal of 646399584 is 485993646.

It is a tau number, because it is divible by the number of its divisors (72).

It is a self number, because there is not a number n which added to its sum of digits gives 646399584.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184602 + ... + 188070.

It is an arithmetic number, because the mean of its divisors is an integer number (25577370).

Almost surely, 2^646399584 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 646399584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (920785320).

646399584 is an abundant number, since it is smaller than the sum of its proper divisors (1195171056).

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

646399584 is a wasteful number, since it uses less digits than its factorization.

646399584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4132 (or 4121 counting only the distinct ones).

The product of its digits is 5598720, while the sum is 54.

The square root of 646399584 is about 25424.3895501937. The cubic root of 646399584 is about 864.6367476948.

The spelling of 646399584 in words is "six hundred forty-six million, three hundred ninety-nine thousand, five hundred eighty-four".