21446666 has 8 divisors (see below), whose sum is σ = 32189700. Its totient is φ = 10716768.

The previous prime is 21446657. The next prime is 21446693. The reversal of 21446666 is 66664412.

It can be written as a sum of positive squares in 2 ways, for example, as 21353641 + 93025 = 4621^2 + 305^2 .

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

21446666 is a modest number, since divided by 6666 gives 2144 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4340 + ... + 7856.

Almost surely, 2^21446666 is an apocalyptic number.

21446666 is a deficient number, since it is larger than the sum of its proper divisors (10743034).

21446666 is a wasteful number, since it uses less digits than its factorization.

21446666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6568.

The product of its digits is 41472, while the sum is 35.

The square root of 21446666 is about 4631.0545235400. The cubic root of 21446666 is about 277.8347706109.

The spelling of 21446666 in words is "twenty-one million, four hundred forty-six thousand, six hundred sixty-six".