20285440 has 96 divisors (see below), whose sum is σ = 55823040. Its totient is φ = 6930432.

The previous prime is 20285431. The next prime is 20285443. The reversal of 20285440 is 4458202.

It is a happy number.

It is a super-2 number, since 2×20285440² = 822998151987200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20285443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71539 + ... + 71821.

It is an arithmetic number, because the mean of its divisors is an integer number (581490).

Almost surely, 2^20285440 is an apocalyptic number.

20285440 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 20285440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27911520).

20285440 is an abundant number, since it is smaller than the sum of its proper divisors (35537600).

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

20285440 is an equidigital number, since it uses as much as digits as its factorization.

20285440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

The square root of 20285440 is about 4503.9360563845. The cubic root of 20285440 is about 272.7270055216.

The spelling of 20285440 in words is "twenty million, two hundred eighty-five thousand, four hundred forty".