21220233137 has 2 divisors, whose sum is σ = 21220233138. Its totient is φ = 21220233136.

The previous prime is 21220233091. The next prime is 21220233161. The reversal of 21220233137 is 73133202212.

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., 16470128896 + 4750104241 = 128336^2 + 68921^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220233137 - 2²⁸ = 20951797681 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220233037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610116568 + 10610116569.

It is an arithmetic number, because the mean of its divisors is an integer number (10610116569).

Almost surely, 2^21220233137 is an apocalyptic number.

It is an amenable number.

21220233137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220233137 is an equidigital number, since it uses as much as digits as its factorization.

21220233137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 26.

Adding to 21220233137 its reverse (73133202212), we get a palindrome (94353435349).

The spelling of 21220233137 in words is "twenty-one billion, two hundred twenty million, two hundred thirty-three thousand, one hundred thirty-seven".