21816223988 has 24 divisors (see below), whose sum is σ = 41330472960. Its totient is φ = 10016304480.

The previous prime is 21816223963. The next prime is 21816223999. The reversal of 21816223988 is 88932261812.

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, 1088348 + ... + 1108211.

It is an arithmetic number, because the mean of its divisors is an integer number (1722103040).

Almost surely, 2^21816223988 is an apocalyptic number.

It is an amenable number.

21816223988 is a deficient number, since it is larger than the sum of its proper divisors (19514248972).

21816223988 is a wasteful number, since it uses less digits than its factorization.

21816223988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196767 (or 2196765 counting only the distinct ones).

The product of its digits is 663552, while the sum is 50.

The spelling of 21816223988 in words is "twenty-one billion, eight hundred sixteen million, two hundred twenty-three thousand, nine hundred eighty-eight".