1315161521 has 4 divisors (see below), whose sum is σ = 1315825392. Its totient is φ = 1314497652.

The previous prime is 1315161517. The next prime is 1315161539. The reversal of 1315161521 is 1251615131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1315161521 - 2² = 1315161517 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1315161541) 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, 328955 + ... + 332928.

It is an arithmetic number, because the mean of its divisors is an integer number (328956348).

Almost surely, 2^1315161521 is an apocalyptic number.

It is an amenable number.

1315161521 is a deficient number, since it is larger than the sum of its proper divisors (663871).

1315161521 is an equidigital number, since it uses as much as digits as its factorization.

1315161521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663870.

The product of its digits is 900, while the sum is 26.

The square root of 1315161521 is about 36265.1557421170. The cubic root of 1315161521 is about 1095.6193603449.

Adding to 1315161521 its reverse (1251615131), we get a palindrome (2566776652).

The spelling of 1315161521 in words is "one billion, three hundred fifteen million, one hundred sixty-one thousand, five hundred twenty-one".