20045440 has 32 divisors (see below), whose sum is σ = 47922660. Its totient is φ = 8017920.

The previous prime is 20045419. The next prime is 20045447. The reversal of 20045440 is 4454002.

It can be written as a sum of positive squares in 2 ways, for example, as 19998784 + 46656 = 4472^2 + 216^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (20045447) 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, 15021 + ... + 16300.

Almost surely, 2^20045440 is an apocalyptic number.

20045440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20045440 is an abundant number, since it is smaller than the sum of its proper divisors (27877220).

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

20045440 is an equidigital number, since it uses as much as digits as its factorization.

20045440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31340 (or 31328 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 19.

The square root of 20045440 is about 4477.2134190811. The cubic root of 20045440 is about 271.6471780634.

Adding to 20045440 its reverse (4454002), we get a palindrome (24499442).

The spelling of 20045440 in words is "twenty million, forty-five thousand, four hundred forty".