21805466 has 8 divisors (see below), whose sum is σ = 32731284. Its totient is φ = 10895040.

The previous prime is 21805463. The next prime is 21805471. The reversal of 21805466 is 66450812.

It can be written as a sum of positive squares in 2 ways, for example, as 21576025 + 229441 = 4645^2 + 479^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21805463) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 836 + ... + 6656.

Almost surely, 2^21805466 is an apocalyptic number.

21805466 is a deficient number, since it is larger than the sum of its proper divisors (10925818).

21805466 is a wasteful number, since it uses less digits than its factorization.

21805466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7696.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 21805466 is about 4669.6323195729. The cubic root of 21805466 is about 279.3755898704.

The spelling of 21805466 in words is "twenty-one million, eight hundred five thousand, four hundred sixty-six".