20211100 has 72 divisors (see below), whose sum is σ = 54003488. Its totient is φ = 6393600.

The previous prime is 20211097. The next prime is 20211109. The reversal of 20211100 is 111202.

It is a Harshad number since it is a multiple of its sum of digits (7).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211109) 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, 7990 + ... + 10210.

Almost surely, 2^20211100 is an apocalyptic number.

20211100 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 20211100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27001744).

20211100 is an abundant number, since it is smaller than the sum of its proper divisors (33792388).

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

20211100 is a wasteful number, since it uses less digits than its factorization.

20211100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2255 (or 2248 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 20211100 is about 4495.6757000478. The cubic root of 20211100 is about 272.3934437354.

Adding to 20211100 its reverse (111202), we get a palindrome (20322302).

The spelling of 20211100 in words is "twenty million, two hundred eleven thousand, one hundred".