31121302213 has 4 divisors (see below), whose sum is σ = 31127394028. Its totient is φ = 31115210400.

The previous prime is 31121302183. The next prime is 31121302253. The reversal of 31121302213 is 31220312113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31220312113 = 317 ⋅98486789.

It can be written as a sum of positive squares in 2 ways, for example, as 6277868289 + 24843433924 = 79233^2 + 157618^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121302213 - 2¹³ = 31121294021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121302253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3038238 + ... + 3048463.

It is an arithmetic number, because the mean of its divisors is an integer number (7781848507).

Almost surely, 2^31121302213 is an apocalyptic number.

It is an amenable number.

31121302213 is a deficient number, since it is larger than the sum of its proper divisors (6091815).

31121302213 is an equidigital number, since it uses as much as digits as its factorization.

31121302213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6091814.

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

Adding to 31121302213 its reverse (31220312113), we get a palindrome (62341614326).

The spelling of 31121302213 in words is "thirty-one billion, one hundred twenty-one million, three hundred two thousand, two hundred thirteen".