1318488721 has 9 divisors (see below), whose sum is σ = 1449687099. Its totient is φ = 1198263000.

The previous prime is 1318488713. The next prime is 1318488733. The reversal of 1318488721 is 1278848131.

The square root of 1318488721 is 36311.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 272613121 + 1045875600 = 16511^2 + 32340^2 .

It is not a de Polignac number, because 1318488721 - 2³ = 1318488713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1318482721) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 397771 + ... + 401071.

Almost surely, 2^1318488721 is an apocalyptic number.

1318488721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1318488721 is the 36311-st square number.

1318488721 is the 18156-th centered octagonal number.

It is an amenable number.

1318488721 is a deficient number, since it is larger than the sum of its proper divisors (131198378).

1318488721 is an frugal number, since it uses more digits than its factorization.

1318488721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6624 (or 3312 counting only the distinct ones).

The product of its digits is 86016, while the sum is 43.

The cubic root of 1318488721 is about 1096.5425105681.

The spelling of 1318488721 in words is "one billion, three hundred eighteen million, four hundred eighty-eight thousand, seven hundred twenty-one".