21255368 has 8 divisors (see below), whose sum is σ = 39853830. Its totient is φ = 10627680.

The previous prime is 21255361. The next prime is 21255383. The reversal of 21255368 is 86355212.

It can be written as a sum of positive squares in only one way, i.e., 14915044 + 6340324 = 3862^2 + 2518^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21255361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1328453 + ... + 1328468.

Almost surely, 2^21255368 is an apocalyptic number.

It is an amenable number.

21255368 is a deficient number, since it is larger than the sum of its proper divisors (18598462).

21255368 is a wasteful number, since it uses less digits than its factorization.

21255368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2656927 (or 2656923 counting only the distinct ones).

The product of its digits is 14400, while the sum is 32.

The square root of 21255368 is about 4610.3544332296. The cubic root of 21255368 is about 277.0062339216.

The spelling of 21255368 in words is "twenty-one million, two hundred fifty-five thousand, three hundred sixty-eight".