13121231021 has 2 divisors, whose sum is σ = 13121231022. Its totient is φ = 13121231020.

The previous prime is 13121231017. The next prime is 13121231059. The reversal of 13121231021 is 12013212131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10965021796 + 2156209225 = 104714^2 + 46435^2 .

It is an emirp because it is prime and its reverse (12013212131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13121231021 - 2² = 13121231017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13121291021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6560615510 + 6560615511.

It is an arithmetic number, because the mean of its divisors is an integer number (6560615511).

Almost surely, 2^13121231021 is an apocalyptic number.

It is an amenable number.

13121231021 is a deficient number, since it is larger than the sum of its proper divisors (1).

13121231021 is an equidigital number, since it uses as much as digits as its factorization.

13121231021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 13121231021 its reverse (12013212131), we get a palindrome (25134443152).

The spelling of 13121231021 in words is "thirteen billion, one hundred twenty-one million, two hundred thirty-one thousand, twenty-one".