21539732 has 12 divisors (see below), whose sum is σ = 38571456. Its totient is φ = 10519320.

The previous prime is 21539729. The next prime is 21539737. The reversal of 21539732 is 23793512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21539737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62444 + ... + 62787.

It is an arithmetic number, because the mean of its divisors is an integer number (3214288).

Almost surely, 2^21539732 is an apocalyptic number.

It is an amenable number.

21539732 is a deficient number, since it is larger than the sum of its proper divisors (17031724).

21539732 is a wasteful number, since it uses less digits than its factorization.

21539732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125278 (or 125276 counting only the distinct ones).

The product of its digits is 11340, while the sum is 32.

The square root of 21539732 is about 4641.0916819214. The cubic root of 21539732 is about 278.2360708921.

The spelling of 21539732 in words is "twenty-one million, five hundred thirty-nine thousand, seven hundred thirty-two".