21118853 has 16 divisors (see below), whose sum is σ = 25708800. Its totient is φ = 17308368.

The previous prime is 21118849. The next prime is 21118883. The reversal of 21118853 is 35881112.

It is not a de Polignac number, because 21118853 - 2² = 21118849 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21118883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6551 + ... + 9227.

It is an arithmetic number, because the mean of its divisors is an integer number (1606800).

Almost surely, 2^21118853 is an apocalyptic number.

21118853 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21118853 is a deficient number, since it is larger than the sum of its proper divisors (4589947).

21118853 is an equidigital number, since it uses as much as digits as its factorization.

21118853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721 (or 2707 counting only the distinct ones).

The product of its digits is 1920, while the sum is 29.

The square root of 21118853 is about 4595.5253236164. The cubic root of 21118853 is about 276.4119251607.

Adding to 21118853 its reverse (35881112), we get a palindrome (56999965).

The spelling of 21118853 in words is "twenty-one million, one hundred eighteen thousand, eight hundred fifty-three".