21661466 has 8 divisors (see below), whose sum is σ = 33025044. Its totient is φ = 10653120.

The previous prime is 21661457. The next prime is 21661477. The reversal of 21661466 is 66416612.

It can be written as a sum of positive squares in 2 ways, for example, as 20025625 + 1635841 = 4475^2 + 1279^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 88655 + ... + 88898.

Almost surely, 2^21661466 is an apocalyptic number.

21661466 is a deficient number, since it is larger than the sum of its proper divisors (11363578).

21661466 is a wasteful number, since it uses less digits than its factorization.

21661466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177616.

The product of its digits is 10368, while the sum is 32.

The square root of 21661466 is about 4654.1880065163. The cubic root of 21661466 is about 278.7592464105.

The spelling of 21661466 in words is "twenty-one million, six hundred sixty-one thousand, four hundred sixty-six".