21717422137 has 2 divisors, whose sum is σ = 21717422138. Its totient is φ = 21717422136.

The previous prime is 21717422107. The next prime is 21717422173. The reversal of 21717422137 is 73122471712.

Together with next prime (21717422173) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12976855056 + 8740567081 = 113916^2 + 93491^2 .

It is a cyclic number.

It is not a de Polignac number, because 21717422137 - 2¹⁹ = 21716897849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21717422096 and 21717422105.

It is not a weakly prime, because it can be changed into another prime (21717422107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10858711068 + 10858711069.

It is an arithmetic number, because the mean of its divisors is an integer number (10858711069).

Almost surely, 2^21717422137 is an apocalyptic number.

It is an amenable number.

21717422137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21717422137 is an equidigital number, since it uses as much as digits as its factorization.

21717422137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32928, while the sum is 37.

Adding to 21717422137 its reverse (73122471712), we get a palindrome (94839893849).

The spelling of 21717422137 in words is "twenty-one billion, seven hundred seventeen million, four hundred twenty-two thousand, one hundred thirty-seven".