31891991039 has 8 divisors (see below), whose sum is σ = 32496282000. Its totient is φ = 31289825152.

The previous prime is 31891991023. The next prime is 31891991063. The reversal of 31891991039 is 93019919813.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31891991039 - 2⁴ = 31891991023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31891991539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 500954 + ... + 561015.

It is an arithmetic number, because the mean of its divisors is an integer number (4062035250).

Almost surely, 2^31891991039 is an apocalyptic number.

31891991039 is a deficient number, since it is larger than the sum of its proper divisors (604290961).

31891991039 is a wasteful number, since it uses less digits than its factorization.

31891991039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1062537.

The product of its (nonzero) digits is 472392, while the sum is 53.

The spelling of 31891991039 in words is "thirty-one billion, eight hundred ninety-one million, nine hundred ninety-one thousand, thirty-nine".