31505312614991 has 2 divisors, whose sum is σ = 31505312614992. Its totient is φ = 31505312614990.

The previous prime is 31505312614957. The next prime is 31505312615009. The reversal of 31505312614991 is 19941621350513.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31505312614991 - 2¹⁰ = 31505312613967 is a prime.

It is a super-2 number, since 2×31505312614991² (a number of 28 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31505312614921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15752656307495 + 15752656307496.

It is an arithmetic number, because the mean of its divisors is an integer number (15752656307496).

Almost surely, 2^{31505312614991} is an apocalyptic number.

31505312614991 is a deficient number, since it is larger than the sum of its proper divisors (1).

31505312614991 is an equidigital number, since it uses as much as digits as its factorization.

31505312614991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 874800, while the sum is 50.

The spelling of 31505312614991 in words is "thirty-one trillion, five hundred five billion, three hundred twelve million, six hundred fourteen thousand, nine hundred ninety-one".