21118700 has 18 divisors (see below), whose sum is σ = 45827796. Its totient is φ = 8447440.

The previous prime is 21118663. The next prime is 21118717. The reversal of 21118700 is 781112.

It is a Harshad number since it is a multiple of its sum of digits (20).

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 5 ways as a sum of consecutive naturals, for example, 105494 + ... + 105693.

Almost surely, 2^21118700 is an apocalyptic number.

21118700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21118700 is an abundant number, since it is smaller than the sum of its proper divisors (24709096).

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

21118700 is a wasteful number, since it uses less digits than its factorization.

21118700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211201 (or 211194 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 21118700 is about 4595.5086769584. The cubic root of 21118700 is about 276.4112576509.

Adding to 21118700 its reverse (781112), we get a palindrome (21899812).

The spelling of 21118700 in words is "twenty-one million, one hundred eighteen thousand, seven hundred".