21505832 has 16 divisors (see below), whose sum is σ = 40406100. Its totient is φ = 10730880.

The previous prime is 21505831. The next prime is 21505859. The reversal of 21505832 is 23850512.

It can be written as a sum of positive squares in 2 ways, for example, as 20557156 + 948676 = 4534^2 + 974^2 .

It is not an unprimeable number, because it can be changed into a prime (21505831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1844 + ... + 6812.

Almost surely, 2^21505832 is an apocalyptic number.

It is an amenable number.

21505832 is a deficient number, since it is larger than the sum of its proper divisors (18900268).

21505832 is a wasteful number, since it uses less digits than its factorization.

21505832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5516 (or 5512 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 21505832 is about 4637.4380858401. The cubic root of 21505832 is about 278.0900282923.

The spelling of 21505832 in words is "twenty-one million, five hundred five thousand, eight hundred thirty-two".