21564822 has 16 divisors (see below), whose sum is σ = 44047872. Its totient is φ = 7035240.

The previous prime is 21564793. The next prime is 21564929. The reversal of 21564822 is 22846512.

It is a self number, because there is not a number n which added to its sum of digits gives 21564822.

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 7 ways as a sum of consecutive naturals, for example, 37954 + ... + 38517.

It is an arithmetic number, because the mean of its divisors is an integer number (2752992).

Almost surely, 2^21564822 is an apocalyptic number.

21564822 is an abundant number, since it is smaller than the sum of its proper divisors (22483050).

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

21564822 is a wasteful number, since it uses less digits than its factorization.

21564822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76523.

The product of its digits is 7680, while the sum is 30.

The square root of 21564822 is about 4643.7939230763. The cubic root of 21564822 is about 278.3440610046.

The spelling of 21564822 in words is "twenty-one million, five hundred sixty-four thousand, eight hundred twenty-two".