20121421331021 has 2 divisors, whose sum is σ = 20121421331022. Its totient is φ = 20121421331020.

The previous prime is 20121421331017. The next prime is 20121421331047. The reversal of 20121421331021 is 12013312412102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16720624315396 + 3400797015625 = 4089086^2 + 1844125^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121421331021 - 2² = 20121421331017 is a prime.

It is a super-2 number, since 2×20121421331021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121421331521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060710665510 + 10060710665511.

It is an arithmetic number, because the mean of its divisors is an integer number (10060710665511).

Almost surely, 2^{20121421331021} is an apocalyptic number.

It is an amenable number.

20121421331021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121421331021 is an equidigital number, since it uses as much as digits as its factorization.

20121421331021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 20121421331021 its reverse (12013312412102), we get a palindrome (32134733743123).

The spelling of 20121421331021 in words is "twenty trillion, one hundred twenty-one billion, four hundred twenty-one million, three hundred thirty-one thousand, twenty-one".