21227666 has 16 divisors (see below), whose sum is σ = 33856704. Its totient is φ = 9959664.

The previous prime is 21227629. The next prime is 21227671. The reversal of 21227666 is 66672212.

It is a super-2 number, since 2×21227666² = 901227607615112, which contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1916 + ... + 6791.

It is an arithmetic number, because the mean of its divisors is an integer number (2116044).

Almost surely, 2^21227666 is an apocalyptic number.

21227666 is a deficient number, since it is larger than the sum of its proper divisors (12629038).

21227666 is a wasteful number, since it uses less digits than its factorization.

21227666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8785.

The product of its digits is 12096, while the sum is 32.

The square root of 21227666 is about 4607.3491293801. The cubic root of 21227666 is about 276.8858413887.

Adding to 21227666 its reverse (66672212), we get a palindrome (87899878).

The spelling of 21227666 in words is "twenty-one million, two hundred twenty-seven thousand, six hundred sixty-six".