1315145561 has 4 divisors (see below), whose sum is σ = 1347222324. Its totient is φ = 1283068800.

The previous prime is 1315145537. The next prime is 1315145597. The reversal of 1315145561 is 1655415131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1655415131 = 199 ⋅8318669.

It can be written as a sum of positive squares in 2 ways, for example, as 76457536 + 1238688025 = 8744^2 + 35195^2 .

It is a cyclic number.

It is not a de Polignac number, because 1315145561 - 2¹⁸ = 1314883417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1315145521) 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, 16038320 + ... + 16038401.

It is an arithmetic number, because the mean of its divisors is an integer number (336805581).

Almost surely, 2^1315145561 is an apocalyptic number.

It is an amenable number.

1315145561 is a deficient number, since it is larger than the sum of its proper divisors (32076763).

1315145561 is an equidigital number, since it uses as much as digits as its factorization.

1315145561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32076762.

The product of its digits is 9000, while the sum is 32.

The square root of 1315145561 is about 36264.9356955172. The cubic root of 1315145561 is about 1095.6149284037.

The spelling of 1315145561 in words is "one billion, three hundred fifteen million, one hundred forty-five thousand, five hundred sixty-one".