21120334021 has 2 divisors, whose sum is σ = 21120334022. Its totient is φ = 21120334020.

The previous prime is 21120333989. The next prime is 21120334073. The reversal of 21120334021 is 12043302112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21110637025 + 9696996 = 145295^2 + 3114^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120334021 - 2⁵ = 21120333989 is a prime.

It is a super-2 number, since 2×21120334021² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21120334021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22120334021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560167010 + 10560167011.

It is an arithmetic number, because the mean of its divisors is an integer number (10560167011).

Almost surely, 2^21120334021 is an apocalyptic number.

It is an amenable number.

21120334021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120334021 is an equidigital number, since it uses as much as digits as its factorization.

21120334021 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 19.

Adding to 21120334021 its reverse (12043302112), we get a palindrome (33163636133).

The spelling of 21120334021 in words is "twenty-one billion, one hundred twenty million, three hundred thirty-four thousand, twenty-one".