318661561 has 8 divisors (see below), whose sum is σ = 325626048. Its totient is φ = 311766000.

The previous prime is 318661547. The next prime is 318661579. The reversal of 318661561 is 165166813.

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 318661561 - 2⁵ = 318661529 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 318661561.

It is not an unprimeable number, because it can be changed into a prime (318661591) 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, 7830 + ... + 26431.

It is an arithmetic number, because the mean of its divisors is an integer number (40703256).

Almost surely, 2^318661561 is an apocalyptic number.

It is an amenable number.

318661561 is a deficient number, since it is larger than the sum of its proper divisors (6964487).

318661561 is a wasteful number, since it uses less digits than its factorization.

318661561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34463.

The product of its digits is 25920, while the sum is 37.

The square root of 318661561 is about 17851.0941121266. The cubic root of 318661561 is about 683.0354216492.

The spelling of 318661561 in words is "three hundred eighteen million, six hundred sixty-one thousand, five hundred sixty-one".