21682213 has 8 divisors (see below), whose sum is σ = 24837120. Its totient is φ = 18541680.

The previous prime is 21682201. The next prime is 21682223. The reversal of 21682213 is 31228612.

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 21682213 - 2⁹ = 21681701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21682223) 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 7 ways as a sum of consecutive naturals, for example, 133 + ... + 6586.

It is an arithmetic number, because the mean of its divisors is an integer number (3104640).

Almost surely, 2^21682213 is an apocalyptic number.

It is an amenable number.

21682213 is a deficient number, since it is larger than the sum of its proper divisors (3154907).

21682213 is an equidigital number, since it uses as much as digits as its factorization.

21682213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7187.

The product of its digits is 1152, while the sum is 25.

The square root of 21682213 is about 4656.4163258884. The cubic root of 21682213 is about 278.8482150372.

The spelling of 21682213 in words is "twenty-one million, six hundred eighty-two thousand, two hundred thirteen".