21671828 has 24 divisors (see below), whose sum is σ = 39096288. Its totient is φ = 10505376.

The previous prime is 21671813. The next prime is 21671831. The reversal of 21671828 is 82817612.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 27650 + ... + 28422.

It is an arithmetic number, because the mean of its divisors is an integer number (1629012).

Almost surely, 2^21671828 is an apocalyptic number.

It is an amenable number.

21671828 is a deficient number, since it is larger than the sum of its proper divisors (17424460).

21671828 is a wasteful number, since it uses less digits than its factorization.

21671828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983 (or 981 counting only the distinct ones).

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

The square root of 21671828 is about 4655.3010643781. The cubic root of 21671828 is about 278.8036885064.

The spelling of 21671828 in words is "twenty-one million, six hundred seventy-one thousand, eight hundred twenty-eight".