21604532 has 6 divisors (see below), whose sum is σ = 37807938. Its totient is φ = 10802264.

The previous prime is 21604529. The next prime is 21604579. The reversal of 21604532 is 23540612.

It can be written as a sum of positive squares in only one way, i.e., 16613776 + 4990756 = 4076^2 + 2234^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21604498 and 21604507.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2700563 + ... + 2700570.

It is an arithmetic number, because the mean of its divisors is an integer number (6301323).

Almost surely, 2^21604532 is an apocalyptic number.

It is an amenable number.

21604532 is a deficient number, since it is larger than the sum of its proper divisors (16203406).

21604532 is a wasteful number, since it uses less digits than its factorization.

21604532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5401137 (or 5401135 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21604532 is about 4648.0675554471. The cubic root of 21604532 is about 278.5148061367.

The spelling of 21604532 in words is "twenty-one million, six hundred four thousand, five hundred thirty-two".