21911828 has 12 divisors (see below), whose sum is σ = 38384640. Its totient is φ = 10944792.

The previous prime is 21911819. The next prime is 21911837. The reversal of 21911828 is 82811912.

It is an interprime number because it is at equal distance from previous prime (21911819) and next prime (21911837).

It is a junction number, because it is equal to n+sod(n) for n = 21911794 and 21911803.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2975 + ... + 7257.

It is an arithmetic number, because the mean of its divisors is an integer number (3198720).

Almost surely, 2^21911828 is an apocalyptic number.

It is an amenable number.

21911828 is a deficient number, since it is larger than the sum of its proper divisors (16472812).

21911828 is a wasteful number, since it uses less digits than its factorization.

21911828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5566 (or 5564 counting only the distinct ones).

The product of its digits is 2304, while the sum is 32.

The square root of 21911828 is about 4681.0071565850. The cubic root of 21911828 is about 279.8290963870.

The spelling of 21911828 in words is "twenty-one million, nine hundred eleven thousand, eight hundred twenty-eight".