918561 has 32 divisors (see below), whose sum is σ = 1548288. Its totient is φ = 472320.

The previous prime is 918539. The next prime is 918563. The reversal of 918561 is 165819.

It is a happy number.

It is not a de Polignac number, because 918561 - 2⁵ = 918529 is a prime.

It is a Curzon number.

918561 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (918563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11026 + ... + 11108.

It is an arithmetic number, because the mean of its divisors is an integer number (48384).

2⁹¹⁸⁵⁶¹ is an apocalyptic number.

It is an amenable number.

918561 is a deficient number, since it is larger than the sum of its proper divisors (629727).

918561 is a wasteful number, since it uses less digits than its factorization.

918561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141.

The product of its digits is 2160, while the sum is 30.

The square root of 918561 is about 958.4158805028. The cubic root of 918561 is about 97.2081476345.

The spelling of 918561 in words is "nine hundred eighteen thousand, five hundred sixty-one".