1315807981 has 8 divisors (see below), whose sum is σ = 1362033720. Its totient is φ = 1269639168.

The previous prime is 1315807979. The next prime is 1315807993. The reversal of 1315807981 is 1897085131.

It can be written as a sum of positive squares in 4 ways, for example, as 662238756 + 653569225 = 25734^2 + 25565^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1315807981 - 2¹ = 1315807979 is a prime.

It is a super-2 number, since 2×1315807981² = 3462701285726592722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1315807081) 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, 35845 + ... + 62581.

It is an arithmetic number, because the mean of its divisors is an integer number (170254215).

Almost surely, 2^1315807981 is an apocalyptic number.

It is an amenable number.

1315807981 is a deficient number, since it is larger than the sum of its proper divisors (46225739).

1315807981 is a wasteful number, since it uses less digits than its factorization.

1315807981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28463.

The product of its (nonzero) digits is 60480, while the sum is 43.

The square root of 1315807981 is about 36274.0676103467. The cubic root of 1315807981 is about 1095.7988460488.

The spelling of 1315807981 in words is "one billion, three hundred fifteen million, eight hundred seven thousand, nine hundred eighty-one".