21255065 has 8 divisors (see below), whose sum is σ = 27468168. Its totient is φ = 15696000.

The previous prime is 21255061. The next prime is 21255077. The reversal of 21255065 is 56055212.

21255065 = T₃₆₆ + T₃₆₇ + ... + T₅₆₀.

It can be written as a sum of positive squares in 4 ways, for example, as 1157776 + 20097289 = 1076^2 + 4483^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21255065 - 2² = 21255061 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21255061) 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 7 ways as a sum of consecutive naturals, for example, 163436 + ... + 163565.

It is an arithmetic number, because the mean of its divisors is an integer number (3433521).

Almost surely, 2^21255065 is an apocalyptic number.

It is an amenable number.

21255065 is a deficient number, since it is larger than the sum of its proper divisors (6213103).

21255065 is a wasteful number, since it uses less digits than its factorization.

21255065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327019.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 21255065 is about 4610.3215722984. The cubic root of 21255065 is about 277.0049176535.

The spelling of 21255065 in words is "twenty-one million, two hundred fifty-five thousand, sixty-five".