21118394 has 8 divisors (see below), whose sum is σ = 34557408. Its totient is φ = 9599260.

The previous prime is 21118381. The next prime is 21118411. The reversal of 21118394 is 49381112.

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

It is an unprimeable number.

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, 479942 + ... + 479985.

It is an arithmetic number, because the mean of its divisors is an integer number (4319676).

Almost surely, 2^21118394 is an apocalyptic number.

21118394 is a deficient number, since it is larger than the sum of its proper divisors (13439014).

21118394 is a wasteful number, since it uses less digits than its factorization.

21118394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 959940.

The product of its digits is 1728, while the sum is 29.

The square root of 21118394 is about 4595.4753834614. The cubic root of 21118394 is about 276.4099226215.

It can be divided in two parts, 21118 and 394, that added together give a palindrome (21512).

The spelling of 21118394 in words is "twenty-one million, one hundred eighteen thousand, three hundred ninety-four".