561311918 has 16 divisors (see below), whose sum is σ = 881206560. Its totient is φ = 267649536.

The previous prime is 561311917. The next prime is 561311921. The reversal of 561311918 is 819113165.

It is a happy number.

561311918 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×561311918³ (a number of 27 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561311917) 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, 2603 + ... + 33606.

It is an arithmetic number, because the mean of its divisors is an integer number (55075410).

Almost surely, 2^561311918 is an apocalyptic number.

561311918 is a deficient number, since it is larger than the sum of its proper divisors (319894642).

561311918 is a wasteful number, since it uses less digits than its factorization.

561311918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36571.

The product of its digits is 6480, while the sum is 35.

The square root of 561311918 is about 23692.0222437849. The cubic root of 561311918 is about 824.9002232563.

The spelling of 561311918 in words is "five hundred sixty-one million, three hundred eleven thousand, nine hundred eighteen".