20395840 has 28 divisors (see below), whose sum is σ = 48568356. Its totient is φ = 8158208.

The previous prime is 20395811. The next prime is 20395841. The reversal of 20395840 is 4859302.

It can be written as a sum of positive squares in 2 ways, for example, as 2214144 + 18181696 = 1488^2 + 4264^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20395841) 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, 31549 + ... + 32188.

Almost surely, 2^20395840 is an apocalyptic number.

20395840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20395840 is an abundant number, since it is smaller than the sum of its proper divisors (28172516).

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

20395840 is an equidigital number, since it uses as much as digits as its factorization.

20395840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63754 (or 63744 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20395840 is about 4516.1753730341. The cubic root of 20395840 is about 273.2208672083.

The spelling of 20395840 in words is "twenty million, three hundred ninety-five thousand, eight hundred forty".