21701255 has 4 divisors (see below), whose sum is σ = 26041512. Its totient is φ = 17361000.

The previous prime is 21701243. The next prime is 21701261. The reversal of 21701255 is 55210712.

It is a happy number.

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

It is not a de Polignac number, because 21701255 - 2⁸ = 21700999 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21701255.

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, 2170121 + ... + 2170130.

It is an arithmetic number, because the mean of its divisors is an integer number (6510378).

Almost surely, 2^21701255 is an apocalyptic number.

21701255 is a deficient number, since it is larger than the sum of its proper divisors (4340257).

21701255 is an equidigital number, since it uses as much as digits as its factorization.

21701255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4340256.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21701255 is about 4658.4605826389. The cubic root of 21701255 is about 278.9298222367.

Adding to 21701255 its reverse (55210712), we get a palindrome (76911967).

The spelling of 21701255 in words is "twenty-one million, seven hundred one thousand, two hundred fifty-five".