21086221 has 8 divisors (see below), whose sum is σ = 23192064. Its totient is φ = 19049520.

The previous prime is 21086203. The next prime is 21086227. The reversal of 21086221 is 12268012.

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

It is a cyclic number.

It is not a de Polignac number, because 21086221 - 2⁹ = 21085709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21086192 and 21086201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21086227) 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, 16645 + ... + 17866.

It is an arithmetic number, because the mean of its divisors is an integer number (2899008).

Almost surely, 2^21086221 is an apocalyptic number.

It is an amenable number.

21086221 is a deficient number, since it is larger than the sum of its proper divisors (2105843).

21086221 is a wasteful number, since it uses less digits than its factorization.

21086221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34571.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21086221 is about 4591.9735408645. The cubic root of 21086221 is about 276.2694849179.

The spelling of 21086221 in words is "twenty-one million, eighty-six thousand, two hundred twenty-one".