21828671 has 2 divisors, whose sum is σ = 21828672. Its totient is φ = 21828670.

The previous prime is 21828659. The next prime is 21828673. The reversal of 21828671 is 17682812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21828671 - 2¹⁰ = 21827647 is a prime.

Together with 21828673, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21828673) 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 as a sum of consecutive naturals, namely, 10914335 + 10914336.

It is an arithmetic number, because the mean of its divisors is an integer number (10914336).

Almost surely, 2^21828671 is an apocalyptic number.

21828671 is a deficient number, since it is larger than the sum of its proper divisors (1).

21828671 is an equidigital number, since it uses as much as digits as its factorization.

21828671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 35.

The square root of 21828671 is about 4672.1163298873. The cubic root of 21828671 is about 279.4746569614.

The spelling of 21828671 in words is "twenty-one million, eight hundred twenty-eight thousand, six hundred seventy-one".