21806404180 has 24 divisors (see below), whose sum is σ = 49956490080. Its totient is φ = 7929601440.

The previous prime is 21806404171. The next prime is 21806404211. The reversal of 21806404180 is 8140460812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49559790 + ... + 49560229.

It is an arithmetic number, because the mean of its divisors is an integer number (2081520420).

Almost surely, 2^21806404180 is an apocalyptic number.

21806404180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21806404180 is an abundant number, since it is smaller than the sum of its proper divisors (28150085900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21806404180 is a wasteful number, since it uses less digits than its factorization.

21806404180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99120039 (or 99120037 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 34.

Adding to 21806404180 its reverse (8140460812), we get a palindrome (29946864992).

The spelling of 21806404180 in words is "twenty-one billion, eight hundred six million, four hundred four thousand, one hundred eighty".