21191268 has 24 divisors (see below), whose sum is σ = 56510272. Its totient is φ = 6054624.

The previous prime is 21191263. The next prime is 21191279. The reversal of 21191268 is 86219112.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21191263) 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, 126055 + ... + 126222.

Almost surely, 2^21191268 is an apocalyptic number.

21191268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21191268 is an abundant number, since it is smaller than the sum of its proper divisors (35319004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21191268 is a wasteful number, since it uses less digits than its factorization.

21191268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252291 (or 252289 counting only the distinct ones).

The product of its digits is 1728, while the sum is 30.

The square root of 21191268 is about 4603.3974410211. The cubic root of 21191268 is about 276.7274968259.

The spelling of 21191268 in words is "twenty-one million, one hundred ninety-one thousand, two hundred sixty-eight".