31709985 has 32 divisors (see below), whose sum is σ = 53498880. Its totient is φ = 16006848.

The previous prime is 31709941. The next prime is 31709987. The reversal of 31709985 is 58990713.

It is a happy number.

It is not a de Polignac number, because 31709985 - 2⁶ = 31709921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31709987) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36486 + ... + 37344.

It is an arithmetic number, because the mean of its divisors is an integer number (1671840).

Almost surely, 2^31709985 is an apocalyptic number.

It is an amenable number.

31709985 is a deficient number, since it is larger than the sum of its proper divisors (21788895).

31709985 is a wasteful number, since it uses less digits than its factorization.

31709985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997.

The product of its (nonzero) digits is 68040, while the sum is 42.

The square root of 31709985 is about 5631.1619582463. The cubic root of 31709985 is about 316.5181938634.

The spelling of 31709985 in words is "thirty-one million, seven hundred nine thousand, nine hundred eighty-five".