21458728866 has 16 divisors (see below), whose sum is σ = 43434536544. Its totient is φ = 7066729824.

The previous prime is 21458728849. The next prime is 21458728909. The reversal of 21458728866 is 66882785412.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21544411 + ... + 21545406.

It is an arithmetic number, because the mean of its divisors is an integer number (2714658534).

Almost surely, 2^21458728866 is an apocalyptic number.

21458728866 is an abundant number, since it is smaller than the sum of its proper divisors (21975807678).

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

21458728866 is a wasteful number, since it uses less digits than its factorization.

21458728866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43089905.

The product of its digits is 10321920, while the sum is 57.

The spelling of 21458728866 in words is "twenty-one billion, four hundred fifty-eight million, seven hundred twenty-eight thousand, eight hundred sixty-six".