21221011121993 has 2 divisors, whose sum is σ = 21221011121994. Its totient is φ = 21221011121992.

The previous prime is 21221011121983. The next prime is 21221011122019. The reversal of 21221011121993 is 39912111012212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16638020734729 + 4582990387264 = 4078973^2 + 2140792^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221011121993 - 2¹⁶ = 21221011056457 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21221011121923) 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, 10610505560996 + 10610505560997.

It is an arithmetic number, because the mean of its divisors is an integer number (10610505560997).

Almost surely, 2^{21221011121993} is an apocalyptic number.

It is an amenable number.

21221011121993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221011121993 is an equidigital number, since it uses as much as digits as its factorization.

21221011121993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 35.

The spelling of 21221011121993 in words is "twenty-one trillion, two hundred twenty-one billion, eleven million, one hundred twenty-one thousand, nine hundred ninety-three".