21084207 has 4 divisors (see below), whose sum is σ = 28112280. Its totient is φ = 14056136.

The previous prime is 21084187. The next prime is 21084227. The reversal of 21084207 is 70248012.

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

It is an interprime number because it is at equal distance from previous prime (21084187) and next prime (21084227).

It is a cyclic number.

It is not a de Polignac number, because 21084207 - 2¹⁸ = 20822063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21084227) 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, 3514032 + ... + 3514037.

It is an arithmetic number, because the mean of its divisors is an integer number (7028070).

Almost surely, 2^21084207 is an apocalyptic number.

21084207 is a deficient number, since it is larger than the sum of its proper divisors (7028073).

21084207 is an equidigital number, since it uses as much as digits as its factorization.

21084207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7028072.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21084207 is about 4591.7542399392. The cubic root of 21084207 is about 276.2606888980.

The spelling of 21084207 in words is "twenty-one million, eighty-four thousand, two hundred seven".