31442778397 has 2 divisors, whose sum is σ = 31442778398. Its totient is φ = 31442778396.

The previous prime is 31442778391. The next prime is 31442778401. The reversal of 31442778397 is 79387724413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28082721241 + 3360057156 = 167579^2 + 57966^2 .

It is an emirp because it is prime and its reverse (79387724413) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31442778397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31442778391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15721389198 + 15721389199.

It is an arithmetic number, because the mean of its divisors is an integer number (15721389199).

Almost surely, 2^31442778397 is an apocalyptic number.

It is an amenable number.

31442778397 is a deficient number, since it is larger than the sum of its proper divisors (1).

31442778397 is an equidigital number, since it uses as much as digits as its factorization.

31442778397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7112448, while the sum is 55.

The spelling of 31442778397 in words is "thirty-one billion, four hundred forty-two million, seven hundred seventy-eight thousand, three hundred ninety-seven".