21326240 has 48 divisors (see below), whose sum is σ = 54264168. Its totient is φ = 7873536.

The previous prime is 21326231. The next prime is 21326309. The reversal of 21326240 is 4262312.

It can be written as a sum of positive squares in 4 ways, for example, as 8737936 + 12588304 = 2956^2 + 3548^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3047 + ... + 7206.

Almost surely, 2^21326240 is an apocalyptic number.

21326240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21326240 is an abundant number, since it is smaller than the sum of its proper divisors (32937928).

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

21326240 is a wasteful number, since it uses less digits than its factorization.

21326240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10281 (or 10273 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21326240 is about 4618.0342138187. The cubic root of 21326240 is about 277.3137673162.

Adding to 21326240 its reverse (4262312), we get a palindrome (25588552).

The spelling of 21326240 in words is "twenty-one million, three hundred twenty-six thousand, two hundred forty".