31691028 has 12 divisors (see below), whose sum is σ = 73945760. Its totient is φ = 10563672.

The previous prime is 31691017. The next prime is 31691039. The reversal of 31691028 is 82019613.

It is an interprime number because it is at equal distance from previous prime (31691017) and next prime (31691039).

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 31690986 and 31691004.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1320448 + ... + 1320471.

Almost surely, 2^31691028 is an apocalyptic number.

It is an amenable number.

31691028 is an abundant number, since it is smaller than the sum of its proper divisors (42254732).

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

31691028 is a wasteful number, since it uses less digits than its factorization.

31691028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640926 (or 2640924 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 31691028 is about 5629.4784838384. The cubic root of 31691028 is about 316.4551071995.

The spelling of 31691028 in words is "thirty-one million, six hundred ninety-one thousand, twenty-eight".