21181882885 has 4 divisors (see below), whose sum is σ = 25418259468. Its totient is φ = 16945506304.

The previous prime is 21181882859. The next prime is 21181882901. The reversal of 21181882885 is 58828818112.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5346680641 + 15835202244 = 73121^2 + 125838^2 .

It is a cyclic number.

It is not a de Polignac number, because 21181882885 - 2¹⁵ = 21181850117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2118188284 + ... + 2118188293.

It is an arithmetic number, because the mean of its divisors is an integer number (6354564867).

Almost surely, 2^21181882885 is an apocalyptic number.

It is an amenable number.

21181882885 is a deficient number, since it is larger than the sum of its proper divisors (4236376583).

21181882885 is an equidigital number, since it uses as much as digits as its factorization.

21181882885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4236376582.

The product of its digits is 655360, while the sum is 52.

The spelling of 21181882885 in words is "twenty-one billion, one hundred eighty-one million, eight hundred eighty-two thousand, eight hundred eighty-five".