21831264 has 288 divisors, whose sum is σ = 82555200. Its totient is φ = 5419008.

The previous prime is 21831263. The next prime is 21831353. The reversal of 21831264 is 46213812.

It is a tau number, because it is divible by the number of its divisors (288).

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 (21831263) 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 47 ways as a sum of consecutive naturals, for example, 1284184 + ... + 1284200.

It is an arithmetic number, because the mean of its divisors is an integer number (286650).

Almost surely, 2^21831264 is an apocalyptic number.

21831264 is a gapful number since it is divisible by the number (24) 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 21831264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41277600).

21831264 is an abundant number, since it is smaller than the sum of its proper divisors (60723936).

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

21831264 is a wasteful number, since it uses less digits than its factorization.

21831264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 42 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21831264 is about 4672.3938190183. The cubic root of 21831264 is about 279.4857226694.

The spelling of 21831264 in words is "twenty-one million, eight hundred thirty-one thousand, two hundred sixty-four".