21121001107021 has 2 divisors, whose sum is σ = 21121001107022. Its totient is φ = 21121001107020.

The previous prime is 21121001107013. The next prime is 21121001107027. The reversal of 21121001107021 is 12070110012112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16747001136100 + 4373999970921 = 4092310^2 + 2091411^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121001107021 - 2³ = 21121001107013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121001107021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121001107027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560500553510 + 10560500553511.

It is an arithmetic number, because the mean of its divisors is an integer number (10560500553511).

Almost surely, 2^{21121001107021} is an apocalyptic number.

It is an amenable number.

21121001107021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121001107021 is an equidigital number, since it uses as much as digits as its factorization.

21121001107021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 19.

Adding to 21121001107021 its reverse (12070110012112), we get a palindrome (33191111119133).

The spelling of 21121001107021 in words is "twenty-one trillion, one hundred twenty-one billion, one million, one hundred seven thousand, twenty-one".