21084087 has 4 divisors (see below), whose sum is σ = 28112120. Its totient is φ = 14056056.

The previous prime is 21084083. The next prime is 21084103. The reversal of 21084087 is 78048012.

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

It is not a de Polignac number, because 21084087 - 2² = 21084083 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21084083) 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, 3514012 + ... + 3514017.

It is an arithmetic number, because the mean of its divisors is an integer number (7028030).

Almost surely, 2^21084087 is an apocalyptic number.

21084087 is a deficient number, since it is larger than the sum of its proper divisors (7028033).

21084087 is an equidigital number, since it uses as much as digits as its factorization.

21084087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7028032.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 21084087 is about 4591.7411730192. The cubic root of 21084087 is about 276.2601647878.

The spelling of 21084087 in words is "twenty-one million, eighty-four thousand, eighty-seven".