31347387818 has 4 divisors (see below), whose sum is σ = 47021081730. Its totient is φ = 15673693908.

The previous prime is 31347387781. The next prime is 31347387821. The reversal of 31347387818 is 81878374313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81878374313 = 101399 ⋅807487.

It can be written as a sum of positive squares in only one way, i.e., 22197126169 + 9150261649 = 148987^2 + 95657^2 .

It is a super-2 number, since 2×31347387818² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31347387818.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7836846953 + ... + 7836846956.

Almost surely, 2^31347387818 is an apocalyptic number.

31347387818 is a deficient number, since it is larger than the sum of its proper divisors (15673693912).

31347387818 is a wasteful number, since it uses less digits than its factorization.

31347387818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15673693911.

The product of its digits is 2709504, while the sum is 53.

The spelling of 31347387818 in words is "thirty-one billion, three hundred forty-seven million, three hundred eighty-seven thousand, eight hundred eighteen".