21828940 has 24 divisors (see below), whose sum is σ = 52389792. Its totient is φ = 7484160.

The previous prime is 21828931. The next prime is 21828949. The reversal of 21828940 is 4982812.

It is an interprime number because it is at equal distance from previous prime (21828931) and next prime (21828949).

It is a junction number, because it is equal to n+sod(n) for n = 21828896 and 21828905.

It is not an unprimeable number, because it can be changed into a prime (21828949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77821 + ... + 78100.

It is an arithmetic number, because the mean of its divisors is an integer number (2182908).

Almost surely, 2^21828940 is an apocalyptic number.

21828940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21828940 is an abundant number, since it is smaller than the sum of its proper divisors (30560852).

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

21828940 is a wasteful number, since it uses less digits than its factorization.

21828940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155937 (or 155935 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 21828940 is about 4672.1451176093. The cubic root of 21828940 is about 279.4758049680.

The spelling of 21828940 in words is "twenty-one million, eight hundred twenty-eight thousand, nine hundred forty".