31681636 has 18 divisors (see below), whose sum is σ = 64495158. Its totient is φ = 13577760.

The previous prime is 31681633. The next prime is 31681673. The reversal of 31681636 is 63618613.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 25401600 + 6280036 = 5040^2 + 2506^2 .

It is not an unprimeable number, because it can be changed into a prime (31681633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 80625 + ... + 81016.

Almost surely, 2^31681636 is an apocalyptic number.

It is an amenable number.

31681636 is an abundant number, since it is smaller than the sum of its proper divisors (32813522).

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

31681636 is a wasteful number, since it uses less digits than its factorization.

31681636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161659 (or 161650 counting only the distinct ones).

The product of its digits is 15552, while the sum is 34.

The square root of 31681636 is about 5628.6442417335. The cubic root of 31681636 is about 316.4238424093.

The spelling of 31681636 in words is "thirty-one million, six hundred eighty-one thousand, six hundred thirty-six".