21088100 has 72 divisors (see below), whose sum is σ = 52600800. Its totient is φ = 7257600.

The previous prime is 21088087. The next prime is 21088141. The reversal of 21088100 is 188012.

It is a super-2 number, since 2×21088100² = 889415923220000, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20396 + ... + 21404.

Almost surely, 2^21088100 is an apocalyptic number.

21088100 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 21088100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26300400).

21088100 is an abundant number, since it is smaller than the sum of its proper divisors (31512700).

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

21088100 is a wasteful number, since it uses less digits than its factorization.

21088100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053 (or 1046 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 21088100 is about 4592.1781324335. The cubic root of 21088100 is about 276.2776908286.

The spelling of 21088100 in words is "twenty-one million, eighty-eight thousand, one hundred".