31012021021 has 2 divisors, whose sum is σ = 31012021022. Its totient is φ = 31012021020.

The previous prime is 31012021009. The next prime is 31012021031. The reversal of 31012021021 is 12012021013.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30979872121 + 32148900 = 176011^2 + 5670^2 .

It is a cyclic number.

It is not a de Polignac number, because 31012021021 - 2²¹ = 31009923869 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31012020992 and 31012021010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31012021031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15506010510 + 15506010511.

It is an arithmetic number, because the mean of its divisors is an integer number (15506010511).

Almost surely, 2^31012021021 is an apocalyptic number.

It is an amenable number.

31012021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31012021021 is an equidigital number, since it uses as much as digits as its factorization.

31012021021 is an evil number, because the sum of its binary digits is even.

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

Adding to 31012021021 its reverse (12012021013), we get a palindrome (43024042034).

The spelling of 31012021021 in words is "thirty-one billion, twelve million, twenty-one thousand, twenty-one".