646979520 has 224 divisors, whose sum is σ = 2259518976. Its totient is φ = 155545600.

The previous prime is 646979519. The next prime is 646979539. The reversal of 646979520 is 25979646.

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

It is a self number, because there is not a number n which added to its sum of digits gives 646979520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2080165 + ... + 2080475.

Almost surely, 2^646979520 is an apocalyptic number.

646979520 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646979520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1129759488).

646979520 is an abundant number, since it is smaller than the sum of its proper divisors (1612539456).

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

646979520 is a wasteful number, since it uses less digits than its factorization.

646979520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539 (or 529 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 48.

The square root of 646979520 is about 25435.7921048274. The cubic root of 646979520 is about 864.8952483217.

The spelling of 646979520 in words is "six hundred forty-six million, nine hundred seventy-nine thousand, five hundred twenty".