21231360 has 216 divisors, whose sum is σ = 78121680. Its totient is φ = 5308416.

The previous prime is 21231359. The next prime is 21231389. The reversal of 21231360 is 6313212.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 23 ways as a sum of consecutive naturals, for example, 218832 + ... + 218928.

Almost surely, 2^21231360 is an apocalyptic number.

21231360 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 21231360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39060840).

21231360 is an abundant number, since it is smaller than the sum of its proper divisors (56890320).

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

21231360 is a wasteful number, since it uses less digits than its factorization.

21231360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21231360 is about 4607.7499932179. The cubic root of 21231360 is about 276.9019015147.

Adding to 21231360 its reverse (6313212), we get a palindrome (27544572).

The spelling of 21231360 in words is "twenty-one million, two hundred thirty-one thousand, three hundred sixty".