21382105 has 4 divisors (see below), whose sum is σ = 25658532. Its totient is φ = 17105680.

The previous prime is 21382103. The next prime is 21382121. The reversal of 21382105 is 50128312.

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 7817616 + 13564489 = 2796^2 + 3683^2 .

It is not a de Polignac number, because 21382105 - 2¹ = 21382103 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21382103) 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, 2138206 + ... + 2138215.

It is an arithmetic number, because the mean of its divisors is an integer number (6414633).

Almost surely, 2^21382105 is an apocalyptic number.

It is an amenable number.

21382105 is a deficient number, since it is larger than the sum of its proper divisors (4276427).

21382105 is an equidigital number, since it uses as much as digits as its factorization.

21382105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4276426.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21382105 is about 4624.0788271828. The cubic root of 21382105 is about 277.5557012878. Note that the first 3 decimals are identical.

The spelling of 21382105 in words is "twenty-one million, three hundred eighty-two thousand, one hundred five".