631686 has 32 divisors (see below), whose sum is σ = 1461888. Its totient is φ = 179840.

The previous prime is 631681. The next prime is 631711. The reversal of 631686 is 686136.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631681) by changing a digit.

631686 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 841 + ... + 1403.

It is an arithmetic number, because the mean of its divisors is an integer number (45684).

2⁶³¹⁶⁸⁶ is an apocalyptic number.

631686 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 631686, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730944).

631686 is an abundant number, since it is smaller than the sum of its proper divisors (830202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

631686 is a wasteful number, since it uses less digits than its factorization.

631686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 596.

The product of its digits is 5184, while the sum is 30.

The square root of 631686 is about 794.7867638556. The cubic root of 631686 is about 85.8025939088.

The spelling of 631686 in words is "six hundred thirty-one thousand, six hundred eighty-six".