21805346 has 8 divisors (see below), whose sum is σ = 32783184. Its totient is φ = 10877620.

The previous prime is 21805327. The next prime is 21805349. The reversal of 21805346 is 64350812.

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

It is a super-2 number, since 2×21805346² = 950946228359432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21805349) by changing a digit.

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, 11420 + ... + 13191.

It is an arithmetic number, because the mean of its divisors is an integer number (4097898).

Almost surely, 2^21805346 is an apocalyptic number.

21805346 is a deficient number, since it is larger than the sum of its proper divisors (10977838).

21805346 is a wasteful number, since it uses less digits than its factorization.

21805346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25056.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21805346 is about 4669.6194705779. The cubic root of 21805346 is about 279.3750773822.

The spelling of 21805346 in words is "twenty-one million, eight hundred five thousand, three hundred forty-six".