31121220313 has 8 divisors (see below), whose sum is σ = 31161083400. Its totient is φ = 31081381248.

The previous prime is 31121220307. The next prime is 31121220343. The reversal of 31121220313 is 31302212113.

It can be written as a sum of positive squares in 4 ways, for example, as 26569 + 31121193744 = 163^2 + 176412^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31121220313 - 2²⁹ = 30584349401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31121220343) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4527243 + ... + 4534111.

It is an arithmetic number, because the mean of its divisors is an integer number (3895135425).

Almost surely, 2^31121220313 is an apocalyptic number.

It is an amenable number.

31121220313 is a deficient number, since it is larger than the sum of its proper divisors (39863087).

31121220313 is a wasteful number, since it uses less digits than its factorization.

31121220313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12011.

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

Adding to 31121220313 its reverse (31302212113), we get a palindrome (62423432426).

The spelling of 31121220313 in words is "thirty-one billion, one hundred twenty-one million, two hundred twenty thousand, three hundred thirteen".