21318132 has 48 divisors (see below), whose sum is σ = 56145600. Its totient is φ = 6236160.

The previous prime is 21318109. The next prime is 21318149. The reversal of 21318132 is 23181312.

It is a junction number, because it is equal to n+sod(n) for n = 21318099 and 21318108.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1044 + ... + 6612.

It is an arithmetic number, because the mean of its divisors is an integer number (1169700).

Almost surely, 2^21318132 is an apocalyptic number.

21318132 is a gapful number since it is divisible by the number (22) 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 21318132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28072800).

21318132 is an abundant number, since it is smaller than the sum of its proper divisors (34827468).

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

21318132 is a wasteful number, since it uses less digits than its factorization.

21318132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5616 (or 5614 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 21318132 is about 4617.1562676609. The cubic root of 21318132 is about 277.2786189883.

Adding to 21318132 its reverse (23181312), we get a palindrome (44499444).

The spelling of 21318132 in words is "twenty-one million, three hundred eighteen thousand, one hundred thirty-two".