21719204 has 54 divisors (see below), whose sum is σ = 43925490. Its totient is φ = 9389952.

The previous prime is 21719197. The next prime is 21719207. The reversal of 21719204 is 40291712.

It can be written as a sum of positive squares in 3 ways, for example, as 577600 + 21141604 = 760^2 + 4598^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21719207) 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 17 ways as a sum of consecutive naturals, for example, 243992 + ... + 244080.

It is an arithmetic number, because the mean of its divisors is an integer number (813435).

Almost surely, 2^21719204 is an apocalyptic number.

It is an amenable number.

21719204 is an abundant number, since it is smaller than the sum of its proper divisors (22206286).

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

21719204 is a wasteful number, since it uses less digits than its factorization.

21719204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21719204 is about 4660.3866792360. The cubic root of 21719204 is about 279.0067015344.

The spelling of 21719204 in words is "twenty-one million, seven hundred nineteen thousand, two hundred four".