21543732 has 180 divisors, whose sum is σ = 69521760. Its totient is φ = 5787936.

The previous prime is 21543727. The next prime is 21543751. The reversal of 21543732 is 23734512.

It is a Harshad number since it is a multiple of its sum of digits (27).

Its product of digits (5040) is a multiple of the sum of its prime factors (112).

It is a junction number, because it is equal to n+sod(n) for n = 21543696 and 21543705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 365119 + ... + 365177.

It is an arithmetic number, because the mean of its divisors is an integer number (386232).

Almost surely, 2^21543732 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 21543732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34760880).

21543732 is an abundant number, since it is smaller than the sum of its proper divisors (47978028).

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

21543732 is a wasteful number, since it uses less digits than its factorization.

21543732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 94 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21543732 is about 4641.5225950113. The cubic root of 21543732 is about 278.2532929479.

It can be divided in two parts, 2154 and 3732, that added together give a triangular number (5886 = T₁₀₈).

The spelling of 21543732 in words is "twenty-one million, five hundred forty-three thousand, seven hundred thirty-two".