31981105291 has 4 divisors (see below), whose sum is σ = 31981623184. Its totient is φ = 31980587400.

The previous prime is 31981105283. The next prime is 31981105301. The reversal of 31981105291 is 19250118913.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31981105291 - 2³ = 31981105283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31981105271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151440 + ... + 294781.

It is an arithmetic number, because the mean of its divisors is an integer number (7995405796).

Almost surely, 2^31981105291 is an apocalyptic number.

31981105291 is a deficient number, since it is larger than the sum of its proper divisors (517893).

31981105291 is an equidigital number, since it uses as much as digits as its factorization.

31981105291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517892.

The product of its (nonzero) digits is 19440, while the sum is 40.

The spelling of 31981105291 in words is "thirty-one billion, nine hundred eighty-one million, one hundred five thousand, two hundred ninety-one".