13021431221 has 2 divisors, whose sum is σ = 13021431222. Its totient is φ = 13021431220.

The previous prime is 13021431187. The next prime is 13021431257. The reversal of 13021431221 is 12213412031.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6891324196 + 6130107025 = 83014^2 + 78295^2 .

It is a cyclic number.

It is not a de Polignac number, because 13021431221 - 2²⁶ = 12954322357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13021431193 and 13021431202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13021431271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6510715610 + 6510715611.

It is an arithmetic number, because the mean of its divisors is an integer number (6510715611).

Almost surely, 2^13021431221 is an apocalyptic number.

It is an amenable number.

13021431221 is a deficient number, since it is larger than the sum of its proper divisors (1).

13021431221 is an equidigital number, since it uses as much as digits as its factorization.

13021431221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 13021431221 its reverse (12213412031), we get a palindrome (25234843252).

The spelling of 13021431221 in words is "thirteen billion, twenty-one million, four hundred thirty-one thousand, two hundred twenty-one".