1315526221 has 4 divisors (see below), whose sum is σ = 1315628572. Its totient is φ = 1315423872.

The previous prime is 1315526189. The next prime is 1315526297. The reversal of 1315526221 is 1226255131.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1226255131 = 283 ⋅4333057.

It can be written as a sum of positive squares in 2 ways, for example, as 1013148900 + 302377321 = 31830^2 + 17389^2 .

It is a cyclic number.

It is not a de Polignac number, because 1315526221 - 2⁵ = 1315526189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1315526221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1315526321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28566 + ... + 58711.

It is an arithmetic number, because the mean of its divisors is an integer number (328907143).

Almost surely, 2^1315526221 is an apocalyptic number.

It is an amenable number.

1315526221 is a deficient number, since it is larger than the sum of its proper divisors (102351).

1315526221 is an equidigital number, since it uses as much as digits as its factorization.

1315526221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102350.

The product of its digits is 3600, while the sum is 28.

The square root of 1315526221 is about 36270.1836361494. The cubic root of 1315526221 is about 1095.7206243204.

The spelling of 1315526221 in words is "one billion, three hundred fifteen million, five hundred twenty-six thousand, two hundred twenty-one".