21121122137 has 2 divisors, whose sum is σ = 21121122138. Its totient is φ = 21121122136.

The previous prime is 21121122107. The next prime is 21121122149. The reversal of 21121122137 is 73122112112.

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., 14128650496 + 6992471641 = 118864^2 + 83621^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121122137 - 2⁶ = 21121122073 is a prime.

It is a super-2 number, since 2×21121122137² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121122107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560561068 + 10560561069.

It is an arithmetic number, because the mean of its divisors is an integer number (10560561069).

Almost surely, 2^21121122137 is an apocalyptic number.

It is an amenable number.

21121122137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121122137 is an equidigital number, since it uses as much as digits as its factorization.

21121122137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 23.

Adding to 21121122137 its reverse (73122112112), we get a palindrome (94243234249).

The spelling of 21121122137 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty-two thousand, one hundred thirty-seven".