20331322121221 has 2 divisors, whose sum is σ = 20331322121222. Its totient is φ = 20331322121220.

The previous prime is 20331322121129. The next prime is 20331322121249. The reversal of 20331322121221 is 12212122313302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18084725832996 + 2246596288225 = 4252614^2 + 1498865^2 .

It is a cyclic number.

It is not a de Polignac number, because 20331322121221 - 2²⁹ = 20330785250309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20331322121021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10165661060610 + 10165661060611.

It is an arithmetic number, because the mean of its divisors is an integer number (10165661060611).

Almost surely, 2^{20331322121221} is an apocalyptic number.

It is an amenable number.

20331322121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20331322121221 is an equidigital number, since it uses as much as digits as its factorization.

20331322121221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 25.

Adding to 20331322121221 its reverse (12212122313302), we get a palindrome (32543444434523).

The spelling of 20331322121221 in words is "twenty trillion, three hundred thirty-one billion, three hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".