20585640 has 64 divisors (see below), whose sum is σ = 65396160. Its totient is φ = 5166080.

The previous prime is 20585627. The next prime is 20585647. The reversal of 20585640 is 4658502.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20585598 and 20585607.

It is not an unprimeable number, because it can be changed into a prime (20585647) 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 15 ways as a sum of consecutive naturals, for example, 3006 + ... + 7085.

It is an arithmetic number, because the mean of its divisors is an integer number (1021815).

Almost surely, 2^20585640 is an apocalyptic number.

20585640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20585640 is an abundant number, since it is smaller than the sum of its proper divisors (44810520).

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

20585640 is a wasteful number, since it uses less digits than its factorization.

20585640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10122 (or 10118 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 20585640 is about 4537.1400683691. The cubic root of 20585640 is about 274.0657664428.

The spelling of 20585640 in words is "twenty million, five hundred eighty-five thousand, six hundred forty".