21813442559 has 4 divisors (see below), whose sum is σ = 22171040040. Its totient is φ = 21455845080.

The previous prime is 21813442549. The next prime is 21813442571. The reversal of 21813442559 is 95524431812.

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 21813442559 - 2⁸ = 21813442303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813442529) 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, 178798649 + ... + 178798770.

It is an arithmetic number, because the mean of its divisors is an integer number (5542760010).

Almost surely, 2^21813442559 is an apocalyptic number.

21813442559 is a deficient number, since it is larger than the sum of its proper divisors (357597481).

21813442559 is an equidigital number, since it uses as much as digits as its factorization.

21813442559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357597480.

The product of its digits is 345600, while the sum is 44.

The spelling of 21813442559 in words is "twenty-one billion, eight hundred thirteen million, four hundred forty-two thousand, five hundred fifty-nine".