21795818 has 8 divisors (see below), whose sum is σ = 35665920. Its totient is φ = 9907180.

The previous prime is 21795817. The next prime is 21795847. The reversal of 21795818 is 81859712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21795817) 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 3 ways as a sum of consecutive naturals, for example, 495338 + ... + 495381.

It is an arithmetic number, because the mean of its divisors is an integer number (4458240).

Almost surely, 2^21795818 is an apocalyptic number.

21795818 is a deficient number, since it is larger than the sum of its proper divisors (13870102).

21795818 is a wasteful number, since it uses less digits than its factorization.

21795818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990732.

The product of its digits is 40320, while the sum is 41.

The square root of 21795818 is about 4668.5991474960. The cubic root of 21795818 is about 279.3343798159.

It can be divided in two parts, 2179 and 5818, that added together give a palindrome (7997).

The spelling of 21795818 in words is "twenty-one million, seven hundred ninety-five thousand, eight hundred eighteen".