31685616 has 120 divisors (see below), whose sum is σ = 96171920. Its totient is φ = 9704448.

The previous prime is 31685587. The next prime is 31685623. The reversal of 31685616 is 61658613.

It is a happy number.

31685616 is a `hidden beast` number, since 31 + 6 + 8 + 5 + 616 = 666.

It is a super-2 number, since 2×31685616² = 2007956522598912, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101076 + ... + 101388.

Almost surely, 2^31685616 is an apocalyptic number.

31685616 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31685616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48085960).

31685616 is an abundant number, since it is smaller than the sum of its proper divisors (64486304).

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

31685616 is a wasteful number, since it uses less digits than its factorization.

31685616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383 (or 374 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 31685616 is about 5628.9977793565. The cubic root of 31685616 is about 316.4370920845.

The spelling of 31685616 in words is "thirty-one million, six hundred eighty-five thousand, six hundred sixteen".