31129986 has 16 divisors (see below), whose sum is σ = 62751744. Its totient is φ = 10294704.

The previous prime is 31129981. The next prime is 31129991. The reversal of 31129986 is 68992113.

It is an interprime number because it is at equal distance from previous prime (31129981) and next prime (31129991).

It is not an unprimeable number, because it can be changed into a prime (31129981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19665 + ... + 21188.

It is an arithmetic number, because the mean of its divisors is an integer number (3921984).

Almost surely, 2^31129986 is an apocalyptic number.

31129986 is an abundant number, since it is smaller than the sum of its proper divisors (31621758).

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

31129986 is a wasteful number, since it uses less digits than its factorization.

31129986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40985.

The product of its digits is 23328, while the sum is 39.

The square root of 31129986 is about 5579.4252392160. The cubic root of 31129986 is about 314.5765234125.

The spelling of 31129986 in words is "thirty-one million, one hundred twenty-nine thousand, nine hundred eighty-six".