31122010021 has 4 divisors (see below), whose sum is σ = 31155511500. Its totient is φ = 31088508544.

The previous prime is 31122009983. The next prime is 31122010043. The reversal of 31122010021 is 12001022113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12001022113 = 37 ⋅324351949.

It can be written as a sum of positive squares in 2 ways, for example, as 10532916900 + 20589093121 = 102630^2 + 143489^2 .

It is a cyclic number.

It is not a de Polignac number, because 31122010021 - 2³³ = 22532075429 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31122009983 and 31122010010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31122010081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16749346 + ... + 16751203.

It is an arithmetic number, because the mean of its divisors is an integer number (7788877875).

Almost surely, 2^31122010021 is an apocalyptic number.

It is an amenable number.

31122010021 is a deficient number, since it is larger than the sum of its proper divisors (33501479).

31122010021 is an equidigital number, since it uses as much as digits as its factorization.

31122010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33501478.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 31122010021 its reverse (12001022113), we get a palindrome (43123032134).

The spelling of 31122010021 in words is "thirty-one billion, one hundred twenty-two million, ten thousand, twenty-one".