21084067 has 4 divisors (see below), whose sum is σ = 21145176. Its totient is φ = 21022960.

The previous prime is 21084047. The next prime is 21084083. The reversal of 21084067 is 76048012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21084067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21084047) 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, 30034 + ... + 30727.

It is an arithmetic number, because the mean of its divisors is an integer number (5286294).

Almost surely, 2^21084067 is an apocalyptic number.

21084067 is a deficient number, since it is larger than the sum of its proper divisors (61109).

21084067 is an equidigital number, since it uses as much as digits as its factorization.

21084067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61108.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21084067 is about 4591.7389951956. The cubic root of 21084067 is about 276.2600774359.

The spelling of 21084067 in words is "twenty-one million, eighty-four thousand, sixty-seven".