21556732 has 6 divisors (see below), whose sum is σ = 37724288. Its totient is φ = 10778364.

The previous prime is 21556709. The next prime is 21556739. The reversal of 21556732 is 23765512.

It is a junction number, because it is equal to n+sod(n) for n = 21556694 and 21556703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2694588 + ... + 2694595.

Almost surely, 2^21556732 is an apocalyptic number.

It is an amenable number.

21556732 is a deficient number, since it is larger than the sum of its proper divisors (16167556).

21556732 is a wasteful number, since it uses less digits than its factorization.

21556732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5389187 (or 5389185 counting only the distinct ones).

The product of its digits is 12600, while the sum is 31.

The square root of 21556732 is about 4642.9227863491. The cubic root of 21556732 is about 278.3092499112.

The spelling of 21556732 in words is "twenty-one million, five hundred fifty-six thousand, seven hundred thirty-two".