21001020122191 has 2 divisors, whose sum is σ = 21001020122192. Its totient is φ = 21001020122190.

The previous prime is 21001020122153. The next prime is 21001020122207. The reversal of 21001020122191 is 19122102010012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001020122191 - 2¹⁹ = 21001019597903 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001020122141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500510061095 + 10500510061096.

It is an arithmetic number, because the mean of its divisors is an integer number (10500510061096).

Almost surely, 2^{21001020122191} is an apocalyptic number.

21001020122191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001020122191 is an equidigital number, since it uses as much as digits as its factorization.

21001020122191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21001020122191 in words is "twenty-one trillion, one billion, twenty million, one hundred twenty-two thousand, one hundred ninety-one".