631521280 has 120 divisors (see below), whose sum is σ = 1634942232. Its totient is φ = 232783872.

The previous prime is 631521269. The next prime is 631521299. The reversal of 631521280 is 82125136.

It can be written as a sum of positive squares in 4 ways, for example, as 21233664 + 610287616 = 4608^2 + 24704^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a cake number, because a cake can be divided into 631521280 parts by 1559 planar cuts.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1064664 + ... + 1065256.

Almost surely, 2^631521280 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 631521280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (817471116).

631521280 is an abundant number, since it is smaller than the sum of its proper divisors (1003420952).

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

631521280 is an equidigital number, since it uses as much as digits as its factorization.

631521280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 631521280 is about 25130.0871466853. The cubic root of 631521280 is about 857.9513522840.

The spelling of 631521280 in words is "six hundred thirty-one million, five hundred twenty-one thousand, two hundred eighty".