21559974811 has 4 divisors (see below), whose sum is σ = 21560398000. Its totient is φ = 21559551624.

The previous prime is 21559974773. The next prime is 21559974827. The reversal of 21559974811 is 11847995512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21559974811 - 2⁹ = 21559974299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21559974841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122736 + ... + 241213.

It is an arithmetic number, because the mean of its divisors is an integer number (5390099500).

Almost surely, 2^21559974811 is an apocalyptic number.

21559974811 is a deficient number, since it is larger than the sum of its proper divisors (423189).

21559974811 is an equidigital number, since it uses as much as digits as its factorization.

21559974811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423188.

The product of its digits is 907200, while the sum is 52.

The spelling of 21559974811 in words is "twenty-one billion, five hundred fifty-nine million, nine hundred seventy-four thousand, eight hundred eleven".