31408377781531 has 2 divisors, whose sum is σ = 31408377781532. Its totient is φ = 31408377781530.

The previous prime is 31408377781507. The next prime is 31408377781579. The reversal of 31408377781531 is 13518777380413.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31408377781531 - 2²⁷ = 31408243563803 is a prime.

It is a super-2 number, since 2×31408377781531² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31408377781591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15704188890765 + 15704188890766.

It is an arithmetic number, because the mean of its divisors is an integer number (15704188890766).

Almost surely, 2^{31408377781531} is an apocalyptic number.

31408377781531 is a deficient number, since it is larger than the sum of its proper divisors (1).

31408377781531 is an equidigital number, since it uses as much as digits as its factorization.

31408377781531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11854080, while the sum is 58.

The spelling of 31408377781531 in words is "thirty-one trillion, four hundred eight billion, three hundred seventy-seven million, seven hundred eighty-one thousand, five hundred thirty-one".