31440172213 has 2 divisors, whose sum is σ = 31440172214. Its totient is φ = 31440172212.

The previous prime is 31440172187. The next prime is 31440172219. The reversal of 31440172213 is 31227104413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30692587249 + 747584964 = 175193^2 + 27342^2 .

It is a cyclic number.

It is not a de Polignac number, because 31440172213 - 2³³ = 22850237621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31440172219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15720086106 + 15720086107.

It is an arithmetic number, because the mean of its divisors is an integer number (15720086107).

Almost surely, 2^31440172213 is an apocalyptic number.

It is an amenable number.

31440172213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31440172213 is an equidigital number, since it uses as much as digits as its factorization.

31440172213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 28.

Adding to 31440172213 its reverse (31227104413), we get a palindrome (62667276626).

The spelling of 31440172213 in words is "thirty-one billion, four hundred forty million, one hundred seventy-two thousand, two hundred thirteen".