21275875 has 8 divisors (see below), whose sum is σ = 26552448. Its totient is φ = 17020600.

The previous prime is 21275873. The next prime is 21275887. The reversal of 21275875 is 57857212.

It is not a de Polignac number, because 21275875 - 2¹ = 21275873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21275873) 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, 84979 + ... + 85228.

It is an arithmetic number, because the mean of its divisors is an integer number (3319056).

Almost surely, 2^21275875 is an apocalyptic number.

21275875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21275875 is a deficient number, since it is larger than the sum of its proper divisors (5276573).

21275875 is an equidigital number, since it uses as much as digits as its factorization.

21275875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170222 (or 170212 counting only the distinct ones).

The product of its digits is 39200, while the sum is 37.

The square root of 21275875 is about 4612.5779126211. The cubic root of 21275875 is about 277.0952897147.

The spelling of 21275875 in words is "twenty-one million, two hundred seventy-five thousand, eight hundred seventy-five".