21204866 has 8 divisors (see below), whose sum is σ = 31852560. Its totient is φ = 10587348.

The previous prime is 21204863. The next prime is 21204871. The reversal of 21204866 is 66840212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21204863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5696 + ... + 8651.

It is an arithmetic number, because the mean of its divisors is an integer number (3981570).

Almost surely, 2^21204866 is an apocalyptic number.

21204866 is a deficient number, since it is larger than the sum of its proper divisors (10647694).

21204866 is a wasteful number, since it uses less digits than its factorization.

21204866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15088.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21204866 is about 4604.8741568039. The cubic root of 21204866 is about 276.7866742808.

The spelling of 21204866 in words is "twenty-one million, two hundred four thousand, eight hundred sixty-six".