21732 has 12 divisors (see below), whose sum is σ = 50736. Its totient is φ = 7240.

The previous prime is 21727. The next prime is 21737. The reversal of 21732 is 23712.

It is an interprime number because it is at equal distance from previous prime (21727) and next prime (21737).

It is a tau number, because it is divible by the number of its divisors (12).

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21732.

It is not an unprimeable number, because it can be changed into a prime (21737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 894 + ... + 917.

It is an arithmetic number, because the mean of its divisors is an integer number (4228).

2²¹⁷³² is an apocalyptic number.

It is an amenable number.

21732 is an abundant number, since it is smaller than the sum of its proper divisors (29004).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25368).

21732 is a wasteful number, since it uses less digits than its factorization.

21732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818 (or 1816 counting only the distinct ones).

The product of its digits is 84, while the sum is 15.

The square root of 21732 is about 147.4177736910. The cubic root of 21732 is about 27.9061483604.

The spelling of 21732 in words is "twenty-one thousand, seven hundred thirty-two".