21420213289 has 2 divisors, whose sum is σ = 21420213290. Its totient is φ = 21420213288.

The previous prime is 21420213229. The next prime is 21420213341. The reversal of 21420213289 is 98231202412.

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., 14159810025 + 7260403264 = 118995^2 + 85208^2 .

It is a cyclic number.

It is not a de Polignac number, because 21420213289 - 2⁷ = 21420213161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21420213229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710106644 + 10710106645.

It is an arithmetic number, because the mean of its divisors is an integer number (10710106645).

Almost surely, 2^21420213289 is an apocalyptic number.

It is an amenable number.

21420213289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420213289 is an equidigital number, since it uses as much as digits as its factorization.

21420213289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21420213289 in words is "twenty-one billion, four hundred twenty million, two hundred thirteen thousand, two hundred eighty-nine".