21543232 has 14 divisors (see below), whose sum is σ = 42749978. Its totient is φ = 10771584.

The previous prime is 21543229. The next prime is 21543241. The reversal of 21543232 is 23234512.

It can be written as a sum of positive squares in only one way, i.e., 18800896 + 2742336 = 4336^2 + 1656^2 .

It is a super-2 number, since 2×21543232² = 928221690011648, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 168243 + ... + 168370.

Almost surely, 2^21543232 is an apocalyptic number.

It is an amenable number.

21543232 is a deficient number, since it is larger than the sum of its proper divisors (21206746).

21543232 is an equidigital number, since it uses as much as digits as its factorization.

21543232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336625 (or 336615 counting only the distinct ones).

The product of its digits is 1440, while the sum is 22.

The square root of 21543232 is about 4641.4687330628. The cubic root of 21543232 is about 278.2511403075.

Adding to 21543232 its reverse (23234512), we get a palindrome (44777744).

The spelling of 21543232 in words is "twenty-one million, five hundred forty-three thousand, two hundred thirty-two".