21422666 has 4 divisors (see below), whose sum is σ = 32134002. Its totient is φ = 10711332.

The previous prime is 21422641. The next prime is 21422689. The reversal of 21422666 is 66622412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 32041 = 4625^2 + 179^2 .

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 as a sum of consecutive naturals, namely, 5355665 + ... + 5355668.

Almost surely, 2^21422666 is an apocalyptic number.

21422666 is a deficient number, since it is larger than the sum of its proper divisors (10711336).

21422666 is a wasteful number, since it uses less digits than its factorization.

21422666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10711335.

The product of its digits is 6912, while the sum is 29.

The square root of 21422666 is about 4628.4625957223. The cubic root of 21422666 is about 277.7310944600.

The spelling of 21422666 in words is "twenty-one million, four hundred twenty-two thousand, six hundred sixty-six".