1561618313 has 8 divisors (see below), whose sum is σ = 1588800960. Its totient is φ = 1534459600.

The previous prime is 1561618309. The next prime is 1561618319. The reversal of 1561618313 is 3138161651.

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 1561618313 - 2² = 1561618309 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561618319) 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, 169988 + ... + 178938.

It is an arithmetic number, because the mean of its divisors is an integer number (198600120).

Almost surely, 2^1561618313 is an apocalyptic number.

It is an amenable number.

1561618313 is a deficient number, since it is larger than the sum of its proper divisors (27182647).

1561618313 is an equidigital number, since it uses as much as digits as its factorization.

1561618313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11967.

The product of its digits is 12960, while the sum is 35.

The square root of 1561618313 is about 39517.3166219570. The cubic root of 1561618313 is about 1160.1789044814.

Adding to 1561618313 its reverse (3138161651), we get a palindrome (4699779964).

The spelling of 1561618313 in words is "one billion, five hundred sixty-one million, six hundred eighteen thousand, three hundred thirteen".