20385680 has 80 divisors (see below), whose sum is σ = 55175040. Its totient is φ = 6859776.

The previous prime is 20385671. The next prime is 20385683. The reversal of 20385680 is 8658302.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (20385683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32732 + ... + 33348.

It is an arithmetic number, because the mean of its divisors is an integer number (689688).

Almost surely, 2^20385680 is an apocalyptic number.

20385680 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 20385680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27587520).

20385680 is an abundant number, since it is smaller than the sum of its proper divisors (34789360).

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

20385680 is a wasteful number, since it uses less digits than its factorization.

20385680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 696 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 20385680 is about 4515.0503873157. The cubic root of 20385680 is about 273.1754921862.

The spelling of 20385680 in words is "twenty million, three hundred eighty-five thousand, six hundred eighty".