21086187 has 8 divisors (see below), whose sum is σ = 28591680. Its totient is φ = 13819080.

The previous prime is 21086179. The next prime is 21086201. The reversal of 21086187 is 78168012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21086187 - 2³ = 21086179 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21086287) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59389 + ... + 59742.

It is an arithmetic number, because the mean of its divisors is an integer number (3573960).

Almost surely, 2^21086187 is an apocalyptic number.

21086187 is a deficient number, since it is larger than the sum of its proper divisors (7505493).

21086187 is a wasteful number, since it uses less digits than its factorization.

21086187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119193.

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 21086187 is about 4591.9698387511. The cubic root of 21086187 is about 276.2693364296.

The spelling of 21086187 in words is "twenty-one million, eighty-six thousand, one hundred eighty-seven".