20445440 has 36 divisors (see below), whose sum is σ = 48976284. Its totient is φ = 8177664.

The previous prime is 20445427. The next prime is 20445443. The reversal of 20445440 is 4454402.

It can be written as a sum of positive squares in 2 ways, for example, as 11397376 + 9048064 = 3376^2 + 3008^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20445443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6707 + ... + 9266.

Almost surely, 2^20445440 is an apocalyptic number.

20445440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20445440 is an abundant number, since it is smaller than the sum of its proper divisors (28530844).

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

20445440 is an equidigital number, since it uses as much as digits as its factorization.

20445440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15994 (or 15980 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 23.

The square root of 20445440 is about 4521.6634107372. The cubic root of 20445440 is about 273.4421669843.

Adding to 20445440 its reverse (4454402), we get a palindrome (24899842).

The spelling of 20445440 in words is "twenty million, four hundred forty-five thousand, four hundred forty".