21070255 has 4 divisors (see below), whose sum is σ = 25284312. Its totient is φ = 16856200.

The previous prime is 21070237. The next prime is 21070267. The reversal of 21070255 is 55207012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21070255 - 2¹⁵ = 21037487 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

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 in 3 ways as a sum of consecutive naturals, for example, 2107021 + ... + 2107030.

It is an arithmetic number, because the mean of its divisors is an integer number (6321078).

Almost surely, 2^21070255 is an apocalyptic number.

21070255 is a deficient number, since it is larger than the sum of its proper divisors (4214057).

21070255 is an equidigital number, since it uses as much as digits as its factorization.

21070255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4214056.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 21070255 is about 4590.2347434527. The cubic root of 21070255 is about 276.1997390185.

Adding to 21070255 its reverse (55207012), we get a palindrome (76277267).

The spelling of 21070255 in words is "twenty-one million, seventy thousand, two hundred fifty-five".