31121320123 has 8 divisors (see below), whose sum is σ = 32850037520. Its totient is φ = 29483349408.

The previous prime is 31121320093. The next prime is 31121320129. The reversal of 31121320123 is 32102312113.

It is not a de Polignac number, because 31121320123 - 2⁵ = 31121320091 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31121320123.

It is not an unprimeable number, because it can be changed into a prime (31121320129) 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 7 ways as a sum of consecutive naturals, for example, 2261790 + ... + 2275507.

It is an arithmetic number, because the mean of its divisors is an integer number (4106254690).

Almost surely, 2^31121320123 is an apocalyptic number.

31121320123 is a deficient number, since it is larger than the sum of its proper divisors (1728717397).

31121320123 is an frugal number, since it uses more digits than its factorization.

31121320123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4537354 (or 4537316 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 31121320123 its reverse (32102312113), we get a palindrome (63223632236).

The spelling of 31121320123 in words is "thirty-one billion, one hundred twenty-one million, three hundred twenty thousand, one hundred twenty-three".