918631 has 8 divisors (see below), whose sum is σ = 1105280. Its totient is φ = 745848.

The previous prime is 918613. The next prime is 918641. The reversal of 918631 is 136819.

It is a happy number.

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 918631 - 2¹¹ = 916583 is a prime.

It is a super-2 number, since 2×918631² = 1687765828322, which contains 22 as substring.

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 918631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (918641) 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, 3321 + ... + 3586.

It is an arithmetic number, because the mean of its divisors is an integer number (138160).

2⁹¹⁸⁶³¹ is an apocalyptic number.

918631 is a deficient number, since it is larger than the sum of its proper divisors (186649).

918631 is a wasteful number, since it uses less digits than its factorization.

918631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6933.

The product of its digits is 1296, while the sum is 28.

The square root of 918631 is about 958.4523984007. The cubic root of 918631 is about 97.2106168581.

Subtracting from 918631 its product of digits (1296), we obtain a triangular number (917335 = T₁₃₅₄).

The spelling of 918631 in words is "nine hundred eighteen thousand, six hundred thirty-one".