21823115557 has 4 divisors (see below), whose sum is σ = 22027070016. Its totient is φ = 21619161100.

The previous prime is 21823115453. The next prime is 21823115579. The reversal of 21823115557 is 75551132812.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21823115557 - 2¹⁵ = 21823082789 is a prime.

It is a super-2 number, since 2×21823115557² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21823115257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101977069 + ... + 101977282.

It is an arithmetic number, because the mean of its divisors is an integer number (5506767504).

Almost surely, 2^21823115557 is an apocalyptic number.

It is an amenable number.

21823115557 is a deficient number, since it is larger than the sum of its proper divisors (203954459).

21823115557 is a wasteful number, since it uses less digits than its factorization.

21823115557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203954458.

The product of its digits is 84000, while the sum is 40.

The spelling of 21823115557 in words is "twenty-one billion, eight hundred twenty-three million, one hundred fifteen thousand, five hundred fifty-seven".