21111212202137 has 2 divisors, whose sum is σ = 21111212202138. Its totient is φ = 21111212202136.

The previous prime is 21111212202133. The next prime is 21111212202221. The reversal of 21111212202137 is 73120221211112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16173821545561 + 4937390656576 = 4021669^2 + 2222024^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111212202137 - 2² = 21111212202133 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111212202133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555606101068 + 10555606101069.

It is an arithmetic number, because the mean of its divisors is an integer number (10555606101069).

Almost surely, 2^{21111212202137} is an apocalyptic number.

It is an amenable number.

21111212202137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111212202137 is an equidigital number, since it uses as much as digits as its factorization.

21111212202137 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21111212202137 its reverse (73120221211112), we get a palindrome (94231433413249).

The spelling of 21111212202137 in words is "twenty-one trillion, one hundred eleven billion, two hundred twelve million, two hundred two thousand, one hundred thirty-seven".