21113331220021 has 2 divisors, whose sum is σ = 21113331220022. Its totient is φ = 21113331220020.

The previous prime is 21113331219997. The next prime is 21113331220061. The reversal of 21113331220021 is 12002213331112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16778444822500 + 4334886397521 = 4096150^2 + 2082039^2 .

It is a cyclic number.

It is not a de Polignac number, because 21113331220021 - 2¹⁵ = 21113331187253 is a prime.

It is a super-2 number, since 2×21113331220021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21113331219974 and 21113331220001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21113331220061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556665610010 + 10556665610011.

It is an arithmetic number, because the mean of its divisors is an integer number (10556665610011).

Almost surely, 2^{21113331220021} is an apocalyptic number.

It is an amenable number.

21113331220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113331220021 is an equidigital number, since it uses as much as digits as its factorization.

21113331220021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

Adding to 21113331220021 its reverse (12002213331112), we get a palindrome (33115544551133).

The spelling of 21113331220021 in words is "twenty-one trillion, one hundred thirteen billion, three hundred thirty-one million, two hundred twenty thousand, twenty-one".