21220013137 has 2 divisors, whose sum is σ = 21220013138. Its totient is φ = 21220013136.

The previous prime is 21220013117. The next prime is 21220013167. The reversal of 21220013137 is 73131002212.

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., 21105116176 + 114896961 = 145276^2 + 10719^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220013137 - 2¹¹ = 21220011089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220013107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610006568 + 10610006569.

It is an arithmetic number, because the mean of its divisors is an integer number (10610006569).

Almost surely, 2^21220013137 is an apocalyptic number.

It is an amenable number.

21220013137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220013137 is an equidigital number, since it uses as much as digits as its factorization.

21220013137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 22.

Adding to 21220013137 its reverse (73131002212), we get a palindrome (94351015349).

The spelling of 21220013137 in words is "twenty-one billion, two hundred twenty million, thirteen thousand, one hundred thirty-seven".