21121111299949 has 2 divisors, whose sum is σ = 21121111299950. Its totient is φ = 21121111299948.

The previous prime is 21121111299887. The next prime is 21121111300007. The reversal of 21121111299949 is 94999211112112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12287079015849 + 8834032284100 = 3505293^2 + 2972210^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121111299949 - 2⁹ = 21121111299437 is a prime.

It is a super-2 number, since 2×21121111299949² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121111299896 and 21121111299905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121111299749) 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, 10560555649974 + 10560555649975.

It is an arithmetic number, because the mean of its divisors is an integer number (10560555649975).

Almost surely, 2^{21121111299949} is an apocalyptic number.

It is an amenable number.

21121111299949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121111299949 is an equidigital number, since it uses as much as digits as its factorization.

21121111299949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 52.

The spelling of 21121111299949 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two hundred ninety-nine thousand, nine hundred forty-nine".