21855734071909 has 24 divisors (see below), whose sum is σ = 23369568165888. Its totient is φ = 20417024617920.

The previous prime is 21855734071837. The next prime is 21855734071937. The reversal of 21855734071909 is 90917043755812.

It is not a de Polignac number, because 21855734071909 - 2¹³ = 21855734063717 is a prime.

It is a super-2 number, since 2×21855734071909² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21855734071309) 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 in 23 ways as a sum of consecutive naturals, for example, 3362227 + ... + 7417279.

It is an arithmetic number, because the mean of its divisors is an integer number (973732006912).

Almost surely, 2^{21855734071909} is an apocalyptic number.

It is an amenable number.

21855734071909 is a deficient number, since it is larger than the sum of its proper divisors (1513834093979).

21855734071909 is a wasteful number, since it uses less digits than its factorization.

21855734071909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4055285 (or 4055248 counting only the distinct ones).

The product of its (nonzero) digits is 19051200, while the sum is 61.

The spelling of 21855734071909 in words is "twenty-one trillion, eight hundred fifty-five billion, seven hundred thirty-four million, seventy-one thousand, nine hundred nine".