31139782831921 has 16 divisors (see below), whose sum is σ = 31367356408080. Its totient is φ = 30913287911680.

The previous prime is 31139782831909. The next prime is 31139782831931. The reversal of 31139782831921 is 12913828793113.

It can be written as a sum of positive squares in 8 ways, for example, as 9377221950625 + 21762560881296 = 3062225^2 + 4665036^2 .

It is a cyclic number.

It is not a de Polignac number, because 31139782831921 - 2²⁹ = 31139245961009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31139782831931) 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 in 15 ways as a sum of consecutive naturals, for example, 74174415 + ... + 74593051.

It is an arithmetic number, because the mean of its divisors is an integer number (1960459775505).

Almost surely, 2^{31139782831921} is an apocalyptic number.

It is an amenable number.

31139782831921 is a deficient number, since it is larger than the sum of its proper divisors (227573576159).

31139782831921 is a wasteful number, since it uses less digits than its factorization.

31139782831921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419924.

The product of its digits is 3919104, while the sum is 58.

The spelling of 31139782831921 in words is "thirty-one trillion, one hundred thirty-nine billion, seven hundred eighty-two million, eight hundred thirty-one thousand, nine hundred twenty-one".