20040040 has 16 divisors (see below), whose sum is σ = 45090180. Its totient is φ = 8016000.

The previous prime is 20039993. The next prime is 20040049. The reversal of 20040040 is 4004002.

It can be written as a sum of positive squares in 2 ways, for example, as 16048036 + 3992004 = 4006^2 + 1998^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 20039999 and 20040026.

It is not an unprimeable number, because it can be changed into a prime (20040049) 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 3 ways as a sum of consecutive naturals, for example, 250461 + ... + 250540.

Almost surely, 2^20040040 is an apocalyptic number.

20040040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20040040 is an abundant number, since it is smaller than the sum of its proper divisors (25050140).

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

20040040 is a wasteful number, since it uses less digits than its factorization.

20040040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501012 (or 501008 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 10.

The square root of 20040040 is about 4476.6103247882. The cubic root of 20040040 is about 271.6227830472.

Adding to 20040040 its reverse (4004002), we get a palindrome (24044042).

The spelling of 20040040 in words is "twenty million, forty thousand, forty".