21191875 has 20 divisors (see below), whose sum is σ = 27160056. Its totient is φ = 16520000.

The previous prime is 21191873. The next prime is 21191917. The reversal of 21191875 is 57819112.

It is a happy number.

It is not a de Polignac number, because 21191875 - 2¹ = 21191873 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 21191875.

It is not an unprimeable number, because it can be changed into a prime (21191873) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25212 + ... + 26038.

Almost surely, 2^21191875 is an apocalyptic number.

21191875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21191875 is a deficient number, since it is larger than the sum of its proper divisors (5968181).

21191875 is an frugal number, since it uses more digits than its factorization.

21191875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 888 (or 873 counting only the distinct ones).

The product of its digits is 5040, while the sum is 34.

The square root of 21191875 is about 4603.4633701160. The cubic root of 21191875 is about 276.7301389831.

The spelling of 21191875 in words is "twenty-one million, one hundred ninety-one thousand, eight hundred seventy-five".