21798324 has 18 divisors (see below), whose sum is σ = 55101410. Its totient is φ = 7266096.

The previous prime is 21798323. The next prime is 21798331. The reversal of 21798324 is 42389712.

It can be written as a sum of positive squares in only one way, i.e., 21790224 + 8100 = 4668^2 + 90^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 605509 = 21798324 / (2 + 1 + 7 + 9 + 8 + 3 + 2 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21798323) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 302719 + ... + 302790.

Almost surely, 2^21798324 is an apocalyptic number.

It is an amenable number.

21798324 is an abundant number, since it is smaller than the sum of its proper divisors (33303086).

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

21798324 is a wasteful number, since it uses less digits than its factorization.

21798324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605519 (or 605514 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21798324 is about 4668.8675286412. The cubic root of 21798324 is about 279.3450850061.

It can be divided in two parts, 21798 and 324, that added together give a palindrome (22122).

The spelling of 21798324 in words is "twenty-one million, seven hundred ninety-eight thousand, three hundred twenty-four".