646520280 has 128 divisors (see below), whose sum is σ = 2224627200. Its totient is φ = 147244032.

The previous prime is 646520263. The next prime is 646520299. The reversal of 646520280 is 82025646.

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, 261691 + ... + 264149.

It is an arithmetic number, because the mean of its divisors is an integer number (17379900).

Almost surely, 2^646520280 is an apocalyptic number.

646520280 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 646520280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1112313600).

646520280 is an abundant number, since it is smaller than the sum of its proper divisors (1578106920).

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

646520280 is a wasteful number, since it uses less digits than its factorization.

646520280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2793 (or 2789 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 646520280 is about 25426.7630657148. The cubic root of 646520280 is about 864.6905594571.

The spelling of 646520280 in words is "six hundred forty-six million, five hundred twenty thousand, two hundred eighty".