21043732 has 12 divisors (see below), whose sum is σ = 36911700. Its totient is φ = 10497536.

The previous prime is 21043691. The next prime is 21043747. The reversal of 21043732 is 23734012.

It can be written as a sum of positive squares in 2 ways, for example, as 4511376 + 16532356 = 2124^2 + 4066^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4063 + ... + 7654.

It is an arithmetic number, because the mean of its divisors is an integer number (3075975).

Almost surely, 2^21043732 is an apocalyptic number.

It is an amenable number.

21043732 is a deficient number, since it is larger than the sum of its proper divisors (15867968).

21043732 is a wasteful number, since it uses less digits than its factorization.

21043732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12170 (or 12168 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21043732 is about 4587.3447657659. The cubic root of 21043732 is about 276.0837979815.

Adding to 21043732 its reverse (23734012), we get a palindrome (44777744).

The spelling of 21043732 in words is "twenty-one million, forty-three thousand, seven hundred thirty-two".