21682279 has 4 divisors (see below), whose sum is σ = 21714984. Its totient is φ = 21649576.

The previous prime is 21682273. The next prime is 21682289. The reversal of 21682279 is 97228612.

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

It is a cyclic number.

It is not a de Polignac number, because 21682279 - 2⁷ = 21682151 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 (21682273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15337 + ... + 16690.

It is an arithmetic number, because the mean of its divisors is an integer number (5428746).

Almost surely, 2^21682279 is an apocalyptic number.

21682279 is a deficient number, since it is larger than the sum of its proper divisors (32705).

21682279 is an equidigital number, since it uses as much as digits as its factorization.

21682279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32704.

The product of its digits is 24192, while the sum is 37.

The square root of 21682279 is about 4656.4234128782. The cubic root of 21682279 is about 278.8484979721.

The spelling of 21682279 in words is "twenty-one million, six hundred eighty-two thousand, two hundred seventy-nine".