21201212112137 has 2 divisors, whose sum is σ = 21201212112138. Its totient is φ = 21201212112136.

The previous prime is 21201212112079. The next prime is 21201212112191. The reversal of 21201212112137 is 73121121210212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16426654986361 + 4774557125776 = 4052981^2 + 2185076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201212112137 - 2⁸ = 21201212111881 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201212112337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600606056068 + 10600606056069.

It is an arithmetic number, because the mean of its divisors is an integer number (10600606056069).

Almost surely, 2^{21201212112137} is an apocalyptic number.

It is an amenable number.

21201212112137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201212112137 is an equidigital number, since it uses as much as digits as its factorization.

21201212112137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 26.

Adding to 21201212112137 its reverse (73121121210212), we get a palindrome (94322333322349).

The spelling of 21201212112137 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, one hundred twelve thousand, one hundred thirty-seven".