21526240 has 96 divisors (see below), whose sum is σ = 54825120. Its totient is φ = 7962624.

The previous prime is 21526237. The next prime is 21526243. The reversal of 21526240 is 4262512.

It is an interprime number because it is at equal distance from previous prime (21526237) and next prime (21526243).

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21526243) 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 15 ways as a sum of consecutive naturals, for example, 221872 + ... + 221968.

It is an arithmetic number, because the mean of its divisors is an integer number (571095).

Almost surely, 2^21526240 is an apocalyptic number.

21526240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21526240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27412560).

21526240 is an abundant number, since it is smaller than the sum of its proper divisors (33298880).

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

21526240 is a wasteful number, since it uses less digits than its factorization.

21526240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21526240 is about 4639.6379169069. The cubic root of 21526240 is about 278.1779651685.

Adding to 21526240 its reverse (4262512), we get a palindrome (25788752).

The spelling of 21526240 in words is "twenty-one million, five hundred twenty-six thousand, two hundred forty".