31881315691 has 8 divisors (see below), whose sum is σ = 32410212768. Its totient is φ = 31356600000.

The previous prime is 31881315689. The next prime is 31881315731. The reversal of 31881315691 is 19651318813.

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 31881315691 - 2¹ = 31881315689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31881315391) 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, 1029970 + ... + 1060471.

It is an arithmetic number, because the mean of its divisors is an integer number (4051276596).

Almost surely, 2^31881315691 is an apocalyptic number.

31881315691 is a deficient number, since it is larger than the sum of its proper divisors (528897077).

31881315691 is a wasteful number, since it uses less digits than its factorization.

31881315691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2090693.

The product of its digits is 155520, while the sum is 46.

The spelling of 31881315691 in words is "thirty-one billion, eight hundred eighty-one million, three hundred fifteen thousand, six hundred ninety-one".