21468905 has 4 divisors (see below), whose sum is σ = 25762692. Its totient is φ = 17175120.

The previous prime is 21468901. The next prime is 21468907. The reversal of 21468905 is 50986412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14776336 + 6692569 = 3844^2 + 2587^2 .

It is not a de Polignac number, because 21468905 - 2² = 21468901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21468901) 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, 2146886 + ... + 2146895.

It is an arithmetic number, because the mean of its divisors is an integer number (6440673).

Almost surely, 2^21468905 is an apocalyptic number.

It is an amenable number.

21468905 is a deficient number, since it is larger than the sum of its proper divisors (4293787).

21468905 is an equidigital number, since it uses as much as digits as its factorization.

21468905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4293786.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 21468905 is about 4633.4549744224. The cubic root of 21468905 is about 277.9307705053.

The spelling of 21468905 in words is "twenty-one million, four hundred sixty-eight thousand, nine hundred five".