20021100 has 72 divisors (see below), whose sum is σ = 63204288. Its totient is φ = 4852800.

The previous prime is 20021093. The next prime is 20021137. The reversal of 20021100 is 112002.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 267 + ... + 6333.

Almost surely, 2^20021100 is an apocalyptic number.

20021100 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 20021100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31602144).

20021100 is an abundant number, since it is smaller than the sum of its proper divisors (43183188).

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

20021100 is a wasteful number, since it uses less digits than its factorization.

20021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6095 (or 6088 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 20021100 is about 4474.4943848439. The cubic root of 20021100 is about 271.5371851296.

Adding to 20021100 its reverse (112002), we get a palindrome (20133102).

The spelling of 20021100 in words is "twenty million, twenty-one thousand, one hundred".