21828090 has 32 divisors (see below), whose sum is σ = 53608896. Its totient is φ = 5685120.

The previous prime is 21828083. The next prime is 21828101. The reversal of 21828090 is 9082812.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon 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 15 ways as a sum of consecutive naturals, for example, 7171 + ... + 9750.

It is an arithmetic number, because the mean of its divisors is an integer number (1675278).

Almost surely, 2^21828090 is an apocalyptic number.

21828090 is an abundant number, since it is smaller than the sum of its proper divisors (31780806).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21828090 is a wasteful number, since it uses less digits than its factorization.

21828090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16974.

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 21828090 is about 4672.0541520834. The cubic root of 21828090 is about 279.4721774057.

The spelling of 21828090 in words is "twenty-one million, eight hundred twenty-eight thousand, ninety".