31689808 has 40 divisors (see below), whose sum is σ = 64058400. Its totient is φ = 15168384.

The previous prime is 31689799. The next prime is 31689809. The reversal of 31689808 is 80898613.

It is a happy number.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31689809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75423 + ... + 75841.

It is an arithmetic number, because the mean of its divisors is an integer number (1601460).

Almost surely, 2^31689808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31689808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32029200).

31689808 is an abundant number, since it is smaller than the sum of its proper divisors (32368592).

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

31689808 is a wasteful number, since it uses less digits than its factorization.

31689808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 619 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 31689808 is about 5629.3701246232. The cubic root of 31689808 is about 316.4510463216.

The spelling of 31689808 in words is "thirty-one million, six hundred eighty-nine thousand, eight hundred eight".