21219444 has 36 divisors (see below), whose sum is σ = 53778816. Its totient is φ = 7054608.

The previous prime is 21219439. The next prime is 21219449. The reversal of 21219444 is 44491212.

It is a happy number.

21219444 is a `hidden beast` number, since 2 + 1 + 219 + 444 = 666.

It is an interprime number because it is at equal distance from previous prime (21219439) and next prime (21219449).

It is a tau number, because it is divible by the number of its divisors (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21219449) 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 11 ways as a sum of consecutive naturals, for example, 24157 + ... + 25019.

It is an arithmetic number, because the mean of its divisors is an integer number (1493856).

Almost surely, 2^21219444 is an apocalyptic number.

It is an amenable number.

21219444 is an abundant number, since it is smaller than the sum of its proper divisors (32559372).

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

21219444 is a wasteful number, since it uses less digits than its factorization.

21219444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556 (or 1551 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21219444 is about 4606.4567728353. The cubic root of 21219444 is about 276.8500885277.

The spelling of 21219444 in words is "twenty-one million, two hundred nineteen thousand, four hundred forty-four".