31440172187 has 2 divisors, whose sum is σ = 31440172188. Its totient is φ = 31440172186.

The previous prime is 31440172163. The next prime is 31440172213. The reversal of 31440172187 is 78127104413.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31440172187 - 2²² = 31435977883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31440172187.

It is not a weakly prime, because it can be changed into another prime (31440172987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15720086093 + 15720086094.

It is an arithmetic number, because the mean of its divisors is an integer number (15720086094).

Almost surely, 2^31440172187 is an apocalyptic number.

31440172187 is a deficient number, since it is larger than the sum of its proper divisors (1).

31440172187 is an equidigital number, since it uses as much as digits as its factorization.

31440172187 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37632, while the sum is 38.

The spelling of 31440172187 in words is "thirty-one billion, four hundred forty million, one hundred seventy-two thousand, one hundred eighty-seven".