20003840 has 44 divisors (see below), whose sum is σ = 47998056. Its totient is φ = 7999488.

The previous prime is 20003833. The next prime is 20003857. The reversal of 20003840 is 4830002.

It is a super-2 number, since 2×20003840² = 800307229491200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3167 + ... + 7073.

Almost surely, 2^20003840 is an apocalyptic number.

20003840 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 20003840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23999028).

20003840 is an abundant number, since it is smaller than the sum of its proper divisors (27994216).

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

20003840 is an equidigital number, since it uses as much as digits as its factorization.

20003840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3932 (or 3914 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 20003840 is about 4472.5652594456. The cubic root of 20003840 is about 271.4591328205.

Adding to 20003840 its reverse (4830002), we get a palindrome (24833842).

The spelling of 20003840 in words is "twenty million, three thousand, eight hundred forty".