20001900 has 72 divisors (see below), whose sum is σ = 58874704. Its totient is φ = 5241600.

The previous prime is 20001899. The next prime is 20001901. The reversal of 20001900 is 910002.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20001899) and next prime (20001901).

It is a super-2 number, since 2×20001900² = 800152007220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (20001901) 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 23 ways as a sum of consecutive naturals, for example, 17754 + ... + 18846.

Almost surely, 2^20001900 is an apocalyptic number.

20001900 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 20001900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29437352).

20001900 is an abundant number, since it is smaller than the sum of its proper divisors (38872804).

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

20001900 is a wasteful number, since it uses less digits than its factorization.

20001900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1171 (or 1164 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 20001900 is about 4472.3483764126. The cubic root of 20001900 is about 271.4503570431.

Adding to 20001900 its reverse (910002), we get a palindrome (20911902).

The spelling of 20001900 in words is "twenty million, one thousand, nine hundred".