21110900 has 72 divisors (see below), whose sum is σ = 49580160. Its totient is φ = 7776000.

The previous prime is 21110899. The next prime is 21110909. The reversal of 21110900 is 901112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77765 + ... + 78035.

Almost surely, 2^21110900 is an apocalyptic number.

21110900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21110900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24790080).

21110900 is an abundant number, since it is smaller than the sum of its proper divisors (28469260).

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

21110900 is a wasteful number, since it uses less digits than its factorization.

21110900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 338 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 14.

The square root of 21110900 is about 4594.6599438914. The cubic root of 21110900 is about 276.3772234648.

It can be divided in two parts, 211 and 10900, that added together give a palindrome (11111).

The spelling of 21110900 in words is "twenty-one million, one hundred ten thousand, nine hundred".