21095222881 has 2 divisors, whose sum is σ = 21095222882. Its totient is φ = 21095222880.

The previous prime is 21095222879. The next prime is 21095222887. The reversal of 21095222881 is 18822259012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20293427025 + 801795856 = 142455^2 + 28316^2 .

It is a cyclic number.

It is not a de Polignac number, because 21095222881 - 2¹ = 21095222879 is a prime.

It is a super-2 number, since 2×21095222881² (a number of 21 digits) contains 22 as substring.

Together with 21095222879, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21095222887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10547611440 + 10547611441.

It is an arithmetic number, because the mean of its divisors is an integer number (10547611441).

Almost surely, 2^21095222881 is an apocalyptic number.

It is an amenable number.

21095222881 is a deficient number, since it is larger than the sum of its proper divisors (1).

21095222881 is an equidigital number, since it uses as much as digits as its factorization.

21095222881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46080, while the sum is 40.

The spelling of 21095222881 in words is "twenty-one billion, ninety-five million, two hundred twenty-two thousand, eight hundred eighty-one".