21819324 has 12 divisors (see below), whose sum is σ = 50911784. Its totient is φ = 7273104.

The previous prime is 21819323. The next prime is 21819331. The reversal of 21819324 is 42391812.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21819291 and 21819300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21819323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 909127 + ... + 909150.

Almost surely, 2^21819324 is an apocalyptic number.

It is an amenable number.

21819324 is an abundant number, since it is smaller than the sum of its proper divisors (29092460).

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

21819324 is a wasteful number, since it uses less digits than its factorization.

21819324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1818284 (or 1818282 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 21819324 is about 4671.1159266282. The cubic root of 21819324 is about 279.4347610746.

The spelling of 21819324 in words is "twenty-one million, eight hundred nineteen thousand, three hundred twenty-four".