21083187 has 4 divisors (see below), whose sum is σ = 28110920. Its totient is φ = 14055456.

The previous prime is 21083177. The next prime is 21083189. The reversal of 21083187 is 78138012.

It is a happy number.

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

It is not a de Polignac number, because 21083187 - 2⁴ = 21083171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21083189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3513862 + ... + 3513867.

It is an arithmetic number, because the mean of its divisors is an integer number (7027730).

Almost surely, 2^21083187 is an apocalyptic number.

21083187 is a deficient number, since it is larger than the sum of its proper divisors (7027733).

21083187 is an equidigital number, since it uses as much as digits as its factorization.

21083187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7027732.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 21083187 is about 4591.6431699338. The cubic root of 21083187 is about 276.2562338977.

The spelling of 21083187 in words is "twenty-one million, eighty-three thousand, one hundred eighty-seven".