655631 has 4 divisors (see below), whose sum is σ = 671664. Its totient is φ = 639600.

The previous prime is 655601. The next prime is 655637. The reversal of 655631 is 136556.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 655631 - 2¹⁸ = 393487 is a prime.

It is a super-2 number, since 2×655631² = 859704016322, which contains 22 as substring.

It is an Ulam number.

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 655631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7955 + ... + 8036.

It is an arithmetic number, because the mean of its divisors is an integer number (167916).

2⁶⁵⁵⁶³¹ is an apocalyptic number.

655631 is a deficient number, since it is larger than the sum of its proper divisors (16033).

655631 is a wasteful number, since it uses less digits than its factorization.

655631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16032.

The product of its digits is 2700, while the sum is 26.

The square root of 655631 is about 809.7104420717. The cubic root of 655631 is about 86.8733348541.

The spelling of 655631 in words is "six hundred fifty-five thousand, six hundred thirty-one".