21121997914949 has 2 divisors, whose sum is σ = 21121997914950. Its totient is φ = 21121997914948.

The previous prime is 21121997914903. The next prime is 21121997914987. The reversal of 21121997914949 is 94941979912112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21081780420100 + 40217494849 = 4591490^2 + 200543^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121997914949 is a prime.

It is a super-2 number, since 2×21121997914949² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121997919949) 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, 10560998957474 + 10560998957475.

It is an arithmetic number, because the mean of its divisors is an integer number (10560998957475).

Almost surely, 2^{21121997914949} is an apocalyptic number.

It is an amenable number.

21121997914949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121997914949 is an equidigital number, since it uses as much as digits as its factorization.

21121997914949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26453952, while the sum is 68.

The spelling of 21121997914949 in words is "twenty-one trillion, one hundred twenty-one billion, nine hundred ninety-seven million, nine hundred fourteen thousand, nine hundred forty-nine".