31023221021 has 16 divisors (see below), whose sum is σ = 34511016624. Its totient is φ = 27701720064.

The previous prime is 31023220999. The next prime is 31023221023. The reversal of 31023221021 is 12012232013.

It can be written as a sum of positive squares in 8 ways, for example, as 9685315396 + 21337905625 = 98414^2 + 146075^2 .

It is a cyclic number.

It is not a de Polignac number, because 31023221021 - 2²⁶ = 30956112157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31023221023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103196 + ... + 269621.

It is an arithmetic number, because the mean of its divisors is an integer number (2156938539).

Almost surely, 2^31023221021 is an apocalyptic number.

It is an amenable number.

31023221021 is a deficient number, since it is larger than the sum of its proper divisors (3487795603).

31023221021 is a wasteful number, since it uses less digits than its factorization.

31023221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373040.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 31023221021 its reverse (12012232013), we get a palindrome (43035453034).

The spelling of 31023221021 in words is "thirty-one billion, twenty-three million, two hundred twenty-one thousand, twenty-one".