21326500 has 96 divisors (see below), whose sum is σ = 53385696. Its totient is φ = 7372800.

The previous prime is 21326479. The next prime is 21326527. The reversal of 21326500 is 562312.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 18249984 + 3076516 = 4272^2 + 1754^2 .

It is a zygodrome in base 9.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 110404 + ... + 110596.

It is an arithmetic number, because the mean of its divisors is an integer number (556101).

Almost surely, 2^21326500 is an apocalyptic number.

21326500 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 21326500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26692848).

21326500 is an abundant number, since it is smaller than the sum of its proper divisors (32059196).

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

21326500 is a wasteful number, since it uses less digits than its factorization.

21326500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21326500 is about 4618.0623642389. The cubic root of 21326500 is about 277.3148942735.

Adding to 21326500 its reverse (562312), we get a palindrome (21888812).

The spelling of 21326500 in words is "twenty-one million, three hundred twenty-six thousand, five hundred".