21410666 has 4 divisors (see below), whose sum is σ = 32116002. Its totient is φ = 10705332.

The previous prime is 21410657. The next prime is 21410693. The reversal of 21410666 is 66601412.

It is a happy number.

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., 19175641 + 2235025 = 4379^2 + 1495^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5352665 + ... + 5352668.

Almost surely, 2^21410666 is an apocalyptic number.

21410666 is a deficient number, since it is larger than the sum of its proper divisors (10705336).

21410666 is a wasteful number, since it uses less digits than its factorization.

21410666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10705335.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21410666 is about 4627.1660873584. The cubic root of 21410666 is about 277.6792273454.

The spelling of 21410666 in words is "twenty-one million, four hundred ten thousand, six hundred sixty-six".