31291905947 has 2 divisors, whose sum is σ = 31291905948. Its totient is φ = 31291905946.

The previous prime is 31291905851. The next prime is 31291905959. The reversal of 31291905947 is 74950919213.

It is a strong prime.

It is an emirp because it is prime and its reverse (74950919213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31291905947 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31291905895 and 31291905904.

It is not a weakly prime, because it can be changed into another prime (31291905977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15645952973 + 15645952974.

It is an arithmetic number, because the mean of its divisors is an integer number (15645952974).

Almost surely, 2^31291905947 is an apocalyptic number.

31291905947 is a deficient number, since it is larger than the sum of its proper divisors (1).

31291905947 is an equidigital number, since it uses as much as digits as its factorization.

31291905947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 612360, while the sum is 50.

The spelling of 31291905947 in words is "thirty-one billion, two hundred ninety-one million, nine hundred five thousand, nine hundred forty-seven".