21021122137 has 2 divisors, whose sum is σ = 21021122138. Its totient is φ = 21021122136.

The previous prime is 21021122071. The next prime is 21021122167. The reversal of 21021122137 is 73122112012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12550496841 + 8470625296 = 112029^2 + 92036^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021122137 - 2⁷ = 21021122009 is a prime.

It is not a weakly prime, because it can be changed into another prime (21021122167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510561068 + 10510561069.

It is an arithmetic number, because the mean of its divisors is an integer number (10510561069).

Almost surely, 2^21021122137 is an apocalyptic number.

It is an amenable number.

21021122137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021122137 is an equidigital number, since it uses as much as digits as its factorization.

21021122137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

Adding to 21021122137 its reverse (73122112012), we get a palindrome (94143234149).

The spelling of 21021122137 in words is "twenty-one billion, twenty-one million, one hundred twenty-two thousand, one hundred thirty-seven".