2315521561 has 4 divisors (see below), whose sum is σ = 2317584592. Its totient is φ = 2313458532.

The previous prime is 2315521543. The next prime is 2315521609. The reversal of 2315521561 is 1651255132.

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 2315521561 - 2⁹ = 2315521049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2315521511) 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, 1029831 + ... + 1032076.

It is an arithmetic number, because the mean of its divisors is an integer number (579396148).

Almost surely, 2^2315521561 is an apocalyptic number.

It is an amenable number.

2315521561 is a deficient number, since it is larger than the sum of its proper divisors (2063031).

2315521561 is a wasteful number, since it uses less digits than its factorization.

2315521561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2063030.

The product of its digits is 9000, while the sum is 31.

The square root of 2315521561 is about 48119.8665937469. The cubic root of 2315521561 is about 1322.9688230312.

Adding to 2315521561 its reverse (1651255132), we get a palindrome (3966776693).

The spelling of 2315521561 in words is "two billion, three hundred fifteen million, five hundred twenty-one thousand, five hundred sixty-one".