21753132 has 48 divisors (see below), whose sum is σ = 55611360. Its totient is φ = 6587392.

The previous prime is 21753131. The next prime is 21753163. The reversal of 21753132 is 23135712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21753131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4078 + ... + 7754.

It is an arithmetic number, because the mean of its divisors is an integer number (1158570).

Almost surely, 2^21753132 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 21753132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27805680).

21753132 is an abundant number, since it is smaller than the sum of its proper divisors (33858228).

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

21753132 is a wasteful number, since it uses less digits than its factorization.

21753132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3730 (or 3728 counting only the distinct ones).

The product of its digits is 1260, while the sum is 24.

The square root of 21753132 is about 4664.0253001029. The cubic root of 21753132 is about 279.1519065882.

Adding to 21753132 its reverse (23135712), we get a palindrome (44888844).

It can be divided in two parts, 2175 and 3132, that multiplied together give a square (6812100 = 2610²).

The spelling of 21753132 in words is "twenty-one million, seven hundred fifty-three thousand, one hundred thirty-two".