21909822 has 16 divisors (see below), whose sum is σ = 47803392. Its totient is φ = 6639320.

The previous prime is 21909817. The next prime is 21909857. The reversal of 21909822 is 22890912.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 165918 + ... + 166049.

It is an arithmetic number, because the mean of its divisors is an integer number (2987712).

Almost surely, 2^21909822 is an apocalyptic number.

21909822 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21909822 is an abundant number, since it is smaller than the sum of its proper divisors (25893570).

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

21909822 is a wasteful number, since it uses less digits than its factorization.

21909822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331983.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21909822 is about 4680.7928815533. The cubic root of 21909822 is about 279.8205567938.

The spelling of 21909822 in words is "twenty-one million, nine hundred nine thousand, eight hundred twenty-two".