21062061221 has 2 divisors, whose sum is σ = 21062061222. Its totient is φ = 21062061220.

The previous prime is 21062061173. The next prime is 21062061253. The reversal of 21062061221 is 12216026012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17231812900 + 3830248321 = 131270^2 + 61889^2 .

It is a cyclic number.

It is not a de Polignac number, because 21062061221 - 2⁶ = 21062061157 is a prime.

It is a super-2 number, since 2×21062061221² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21062061271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10531030610 + 10531030611.

It is an arithmetic number, because the mean of its divisors is an integer number (10531030611).

Almost surely, 2^21062061221 is an apocalyptic number.

It is an amenable number.

21062061221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21062061221 is an equidigital number, since it uses as much as digits as its factorization.

21062061221 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 21062061221 its reverse (12216026012), we get a palindrome (33278087233).

The spelling of 21062061221 in words is "twenty-one billion, sixty-two million, sixty-one thousand, two hundred twenty-one".