31121012021 has 16 divisors (see below), whose sum is σ = 34930621440. Its totient is φ = 27477564480.

The previous prime is 31121012011. The next prime is 31121012029. The reversal of 31121012021 is 12021012113.

It is a cyclic number.

It is not a de Polignac number, because 31121012021 - 2¹⁰ = 31121010997 is a prime.

It is a super-2 number, since 2×31121012021² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31121011987 and 31121012005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121012029) 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 15 ways as a sum of consecutive naturals, for example, 158060 + ... + 295338.

It is an arithmetic number, because the mean of its divisors is an integer number (2183163840).

Almost surely, 2^31121012021 is an apocalyptic number.

It is an amenable number.

31121012021 is a deficient number, since it is larger than the sum of its proper divisors (3809609419).

31121012021 is a wasteful number, since it uses less digits than its factorization.

31121012021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137884.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 31121012021 its reverse (12021012113), we get a palindrome (43142024134).

The spelling of 31121012021 in words is "thirty-one billion, one hundred twenty-one million, twelve thousand, twenty-one".