21804039124 has 12 divisors (see below), whose sum is σ = 43608078304. Its totient is φ = 9344588184.

The previous prime is 21804039041. The next prime is 21804039221. The reversal of 21804039124 is 42193040812.

21804039124 is an admirable number.

It is a super-2 number, since 2×21804039124² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21804039124.

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, 389357814 + ... + 389357869.

Almost surely, 2^21804039124 is an apocalyptic number.

It is an amenable number.

21804039124 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21804039124 is a wasteful number, since it uses less digits than its factorization.

21804039124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778715694 (or 778715692 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

Adding to 21804039124 its reverse (42193040812), we get a palindrome (63997079936).

The spelling of 21804039124 in words is "twenty-one billion, eight hundred four million, thirty-nine thousand, one hundred twenty-four".