20213100 has 108 divisors (see below), whose sum is σ = 65176384. Its totient is φ = 5235840.

The previous prime is 20213099. The next prime is 20213107. The reversal of 20213100 is 131202.

It is a happy number.

It is a super-2 number, since 2×20213100² = 817138823220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (20213107) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 32997 + ... + 33603.

Almost surely, 2^20213100 is an apocalyptic number.

20213100 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 20213100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32588192).

20213100 is an abundant number, since it is smaller than the sum of its proper divisors (44963284).

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

20213100 is a wasteful number, since it uses less digits than its factorization.

20213100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664 (or 654 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 20213100 is about 4495.8981305185. The cubic root of 20213100 is about 272.4024283844.

Adding to 20213100 its reverse (131202), we get a palindrome (20344302).

The spelling of 20213100 in words is "twenty million, two hundred thirteen thousand, one hundred".