20000840 has 64 divisors (see below), whose sum is σ = 48470400. Its totient is φ = 7400448.

The previous prime is 20000839. The next prime is 20000843. The reversal of 20000840 is 4800002.

It is not an unprimeable number, because it can be changed into a prime (20000843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45341 + ... + 45779.

It is an arithmetic number, because the mean of its divisors is an integer number (757350).

Almost surely, 2^20000840 is an apocalyptic number.

20000840 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 20000840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24235200).

20000840 is an abundant number, since it is smaller than the sum of its proper divisors (28469560).

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

20000840 is a wasteful number, since it uses less digits than its factorization.

20000840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 20000840 is about 4472.2298688685. The cubic root of 20000840 is about 271.4455617910.

Adding to 20000840 its reverse (4800002), we get a palindrome (24800842).

The spelling of 20000840 in words is "twenty million, eight hundred forty", and thus it is an aban number.