31002111981 has 12 divisors (see below), whose sum is σ = 44784798240. Its totient is φ = 20666242440.

The previous prime is 31002111979. The next prime is 31002111983. The reversal of 31002111981 is 18911120013.

It is an interprime number because it is at equal distance from previous prime (31002111979) and next prime (31002111983).

It is not a de Polignac number, because 31002111981 - 2¹ = 31002111979 is a prime.

It is a super-2 number, since 2×31002111981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31002111983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41241 + ... + 252398.

It is an arithmetic number, because the mean of its divisors is an integer number (3732066520).

Almost surely, 2^31002111981 is an apocalyptic number.

It is an amenable number.

31002111981 is a deficient number, since it is larger than the sum of its proper divisors (13782686259).

31002111981 is a wasteful number, since it uses less digits than its factorization.

31002111981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305376 (or 305373 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 27.

Adding to 31002111981 its reverse (18911120013), we get a palindrome (49913231994).

The spelling of 31002111981 in words is "thirty-one billion, two million, one hundred eleven thousand, nine hundred eighty-one".