31311121021 has 16 divisors (see below), whose sum is σ = 31819442688. Its totient is φ = 30807831600.

The previous prime is 31311121007. The next prime is 31311121031. The reversal of 31311121021 is 12012111313.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 31311121021 - 2¹¹ = 31311118973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31311120986 and 31311121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31311121031) 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 15 ways as a sum of consecutive naturals, for example, 10397406 + ... + 10400416.

It is an arithmetic number, because the mean of its divisors is an integer number (1988715168).

Almost surely, 2^31311121021 is an apocalyptic number.

It is an amenable number.

31311121021 is a deficient number, since it is larger than the sum of its proper divisors (508321667).

31311121021 is a wasteful number, since it uses less digits than its factorization.

31311121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3792.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 31311121021 its reverse (12012111313), we get a palindrome (43323232334).

The spelling of 31311121021 in words is "thirty-one billion, three hundred eleven million, one hundred twenty-one thousand, twenty-one".