1320631728 has 40 divisors (see below), whose sum is σ = 3674066928. Its totient is φ = 406348032.

The previous prime is 1320631721. The next prime is 1320631729. The reversal of 1320631728 is 8271360231.

It is a super-2 number, since 2×1320631728² = 3488136322000531968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1320631721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1057575 + ... + 1058822.

Almost surely, 2^1320631728 is an apocalyptic number.

It is an amenable number.

1320631728 is an abundant number, since it is smaller than the sum of its proper divisors (2353435200).

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

1320631728 is a wasteful number, since it uses less digits than its factorization.

1320631728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2116421 (or 2116415 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 1320631728 is about 36340.4970797043. The cubic root of 1320631728 is about 1097.1362778236.

Adding to 1320631728 its reverse (8271360231), we get a palindrome (9591991959).

The spelling of 1320631728 in words is "one billion, three hundred twenty million, six hundred thirty-one thousand, seven hundred twenty-eight".