21609076 has 12 divisors (see below), whose sum is σ = 37878372. Its totient is φ = 10786688.

The previous prime is 21609053. The next prime is 21609083. The reversal of 21609076 is 67090612.

It can be written as a sum of positive squares in 2 ways, for example, as 10719076 + 10890000 = 3274^2 + 3300^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1525 + ... + 6748.

It is an arithmetic number, because the mean of its divisors is an integer number (3156531).

Almost surely, 2^21609076 is an apocalyptic number.

It is an amenable number.

21609076 is a deficient number, since it is larger than the sum of its proper divisors (16269296).

21609076 is a wasteful number, since it uses less digits than its factorization.

21609076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8930 (or 8928 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 21609076 is about 4648.5563350356. The cubic root of 21609076 is about 278.5343310920.

Adding to 21609076 its reverse (67090612), we get a palindrome (88699688).

Subtracting 21609076 from its reverse (67090612), we obtain a square (45481536 = 6744²).

It can be divided in two parts, 2160 and 9076, that added together give a square (11236 = 106²).

The spelling of 21609076 in words is "twenty-one million, six hundred nine thousand, seventy-six".