21813336 has 96 divisors (see below), whose sum is σ = 63273600. Its totient is φ = 6773760.

The previous prime is 21813331. The next prime is 21813343. The reversal of 21813336 is 63331812.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813331) 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 23 ways as a sum of consecutive naturals, for example, 64560 + ... + 64896.

It is an arithmetic number, because the mean of its divisors is an integer number (659100).

Almost surely, 2^21813336 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21813336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31636800).

21813336 is an abundant number, since it is smaller than the sum of its proper divisors (41460264).

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

21813336 is a wasteful number, since it uses less digits than its factorization.

21813336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 402 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21813336 is about 4670.4749223179. The cubic root of 21813336 is about 279.4091964507.

The spelling of 21813336 in words is "twenty-one million, eight hundred thirteen thousand, three hundred thirty-six".