21828815 has 8 divisors (see below), whose sum is σ = 27573360. Its totient is φ = 16543872.

The previous prime is 21828803. The next prime is 21828823. The reversal of 21828815 is 51882812.

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 21828815 - 2⁸ = 21828559 is a prime.

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, 114794 + ... + 114983.

It is an arithmetic number, because the mean of its divisors is an integer number (3446670).

Almost surely, 2^21828815 is an apocalyptic number.

21828815 is a deficient number, since it is larger than the sum of its proper divisors (5744545).

21828815 is a wasteful number, since it uses less digits than its factorization.

21828815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229801.

The product of its digits is 10240, while the sum is 35.

The square root of 21828815 is about 4672.1317404371. The cubic root of 21828815 is about 279.4752715089.

The spelling of 21828815 in words is "twenty-one million, eight hundred twenty-eight thousand, eight hundred fifteen".