19812100 has 144 divisors (see below), whose sum is σ = 55996416. Its totient is φ = 5904000.

The previous prime is 19812097. The next prime is 19812103. The reversal of 19812100 is 121891.

It is an interprime number because it is at equal distance from previous prime (19812097) and next prime (19812103).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (19812103) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 238659 + ... + 238741.

It is an arithmetic number, because the mean of its divisors is an integer number (388864).

Almost surely, 2^19812100 is an apocalyptic number.

19812100 is a gapful number since it is divisible by the number (10) 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 19812100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27998208).

19812100 is an abundant number, since it is smaller than the sum of its proper divisors (36184316).

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

19812100 is a wasteful number, since it uses less digits than its factorization.

19812100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 19812100 is about 4451.0785209879. The cubic root of 19812100 is about 270.5890204395.

Adding to 19812100 its reverse (121891), we get a palindrome (19933991).

The spelling of 19812100 in words is "nineteen million, eight hundred twelve thousand, one hundred".