21866458 has 8 divisors (see below), whose sum is σ = 32824980. Its totient is φ = 10924800.

The previous prime is 21866447. The next prime is 21866459. The reversal of 21866458 is 85466812.

It can be written as a sum of positive squares in 2 ways, for example, as 18722929 + 3143529 = 4327^2 + 1773^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21866458.

It is not an unprimeable number, because it can be changed into a prime (21866459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213 + ... + 6616.

Almost surely, 2^21866458 is an apocalyptic number.

21866458 is a deficient number, since it is larger than the sum of its proper divisors (10958522).

21866458 is a wasteful number, since it uses less digits than its factorization.

21866458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8432.

The product of its digits is 92160, while the sum is 40.

The square root of 21866458 is about 4676.1584660916. The cubic root of 21866458 is about 279.6358275773.

The spelling of 21866458 in words is "twenty-one million, eight hundred sixty-six thousand, four hundred fifty-eight".