21281784268 has 12 divisors (see below), whose sum is σ = 37370234160. Its totient is φ = 10604574512.

The previous prime is 21281784263. The next prime is 21281784281. The reversal of 21281784268 is 86248718212.

It is not an unprimeable number, because it can be changed into a prime (21281784263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9078088 + ... + 9080431.

It is an arithmetic number, because the mean of its divisors is an integer number (3114186180).

Almost surely, 2^21281784268 is an apocalyptic number.

It is an amenable number.

21281784268 is a deficient number, since it is larger than the sum of its proper divisors (16088449892).

21281784268 is a wasteful number, since it uses less digits than its factorization.

21281784268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18158816 (or 18158814 counting only the distinct ones).

The product of its digits is 688128, while the sum is 49.

The spelling of 21281784268 in words is "twenty-one billion, two hundred eighty-one million, seven hundred eighty-four thousand, two hundred sixty-eight".