21214445621 has 2 divisors, whose sum is σ = 21214445622. Its totient is φ = 21214445620.

The previous prime is 21214445587. The next prime is 21214445647. The reversal of 21214445621 is 12654441212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12636907396 + 8577538225 = 112414^2 + 92615^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214445621 - 2¹⁰ = 21214444597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21214445221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607222810 + 10607222811.

It is an arithmetic number, because the mean of its divisors is an integer number (10607222811).

Almost surely, 2^21214445621 is an apocalyptic number.

It is an amenable number.

21214445621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21214445621 is an equidigital number, since it uses as much as digits as its factorization.

21214445621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15360, while the sum is 32.

Adding to 21214445621 its reverse (12654441212), we get a palindrome (33868886833).

The spelling of 21214445621 in words is "twenty-one billion, two hundred fourteen million, four hundred forty-five thousand, six hundred twenty-one".