21022155618791 has 2 divisors, whose sum is σ = 21022155618792. Its totient is φ = 21022155618790.

The previous prime is 21022155618689. The next prime is 21022155618829. The reversal of 21022155618791 is 19781655122012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21022155618791 - 2¹⁴ = 21022155602407 is a prime.

It is a super-2 number, since 2×21022155618791² (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 (21022155618091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511077809395 + 10511077809396.

It is an arithmetic number, because the mean of its divisors is an integer number (10511077809396).

Almost surely, 2^{21022155618791} is an apocalyptic number.

21022155618791 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022155618791 is an equidigital number, since it uses as much as digits as its factorization.

21022155618791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 604800, while the sum is 50.

The spelling of 21022155618791 in words is "twenty-one trillion, twenty-two billion, one hundred fifty-five million, six hundred eighteen thousand, seven hundred ninety-one".