1231021021 has 2 divisors, whose sum is σ = 1231021022. Its totient is φ = 1231021020.

The previous prime is 1231021013. The next prime is 1231021049. The reversal of 1231021021 is 1201201321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 704318521 + 526702500 = 26539^2 + 22950^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231021021 - 2³ = 1231021013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1231020992 and 1231021010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231021061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615510510 + 615510511.

It is an arithmetic number, because the mean of its divisors is an integer number (615510511).

Almost surely, 2^1231021021 is an apocalyptic number.

It is an amenable number.

1231021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231021021 is an equidigital number, since it uses as much as digits as its factorization.

1231021021 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.

The square root of 1231021021 is about 35085.9091516808. The cubic root of 1231021021 is about 1071.7376549149.

Adding to 1231021021 its reverse (1201201321), we get a palindrome (2432222342).

The spelling of 1231021021 in words is "one billion, two hundred thirty-one million, twenty-one thousand, twenty-one".