21728284154018 has 24 divisors (see below), whose sum is σ = 36153180570276. Its totient is φ = 9783842764800.

The previous prime is 21728284153973. The next prime is 21728284154039. The reversal of 21728284154018 is 81045148282712.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2652328188409 + 19075955965609 = 1628597^2 + 4367603^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 783947903 + ... + 783975618.

Almost surely, 2^{21728284154018} is an apocalyptic number.

21728284154018 is a deficient number, since it is larger than the sum of its proper divisors (14424896416258).

21728284154018 is a wasteful number, since it uses less digits than its factorization.

21728284154018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1567923590 (or 1567923577 counting only the distinct ones).

The product of its (nonzero) digits is 2293760, while the sum is 53.

The spelling of 21728284154018 in words is "twenty-one trillion, seven hundred twenty-eight billion, two hundred eighty-four million, one hundred fifty-four thousand, eighteen".