20665760 has 48 divisors (see below), whose sum is σ = 49764456. Its totient is φ = 8107008.

The previous prime is 20665741. The next prime is 20665769. The reversal of 20665760 is 6756602.

It can be written as a sum of positive squares in 4 ways, for example, as 20539024 + 126736 = 4532^2 + 356^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (20665769) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7262 + ... + 9698.

Almost surely, 2^20665760 is an apocalyptic number.

20665760 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 20665760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24882228).

20665760 is an abundant number, since it is smaller than the sum of its proper divisors (29098696).

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

20665760 is a wasteful number, since it uses less digits than its factorization.

20665760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2505 (or 2497 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 20665760 is about 4545.9608445300. The cubic root of 20665760 is about 274.4208638693.

The spelling of 20665760 in words is "twenty million, six hundred sixty-five thousand, seven hundred sixty".