21179868 has 24 divisors (see below), whose sum is σ = 50117760. Its totient is φ = 6960240.

The previous prime is 21179867. The next prime is 21179869. The reversal of 21179868 is 86897112.

It is an interprime number because it is at equal distance from previous prime (21179867) and next prime (21179869).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21179861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11578 + ... + 13281.

It is an arithmetic number, because the mean of its divisors is an integer number (2088240).

Almost surely, 2^21179868 is an apocalyptic number.

It is an amenable number.

21179868 is an abundant number, since it is smaller than the sum of its proper divisors (28937892).

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

21179868 is a wasteful number, since it uses less digits than its factorization.

21179868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24937 (or 24935 counting only the distinct ones).

The product of its digits is 48384, while the sum is 42.

The square root of 21179868 is about 4602.1590585289. The cubic root of 21179868 is about 276.6778653876.

The spelling of 21179868 in words is "twenty-one million, one hundred seventy-nine thousand, eight hundred sixty-eight".