31685436 has 18 divisors (see below), whose sum is σ = 80093832. Its totient is φ = 10561800.

The previous prime is 31685393. The next prime is 31685443. The reversal of 31685436 is 63458613.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×31685436³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 880151 = 31685436 / (3 + 1 + 6 + 8 + 5 + 4 + 3 + 6).

It is a nialpdrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 31685436.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 440040 + ... + 440111.

Almost surely, 2^31685436 is an apocalyptic number.

31685436 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

31685436 is an abundant number, since it is smaller than the sum of its proper divisors (48408396).

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

31685436 is a wasteful number, since it uses less digits than its factorization.

31685436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880161 (or 880156 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 31685436 is about 5628.9817906971. The cubic root of 31685436 is about 316.4364928769.

The spelling of 31685436 in words is "thirty-one million, six hundred eighty-five thousand, four hundred thirty-six".