20280660 has 96 divisors (see below), whose sum is σ = 61326720. Its totient is φ = 4988928.

The previous prime is 20280607. The next prime is 20280661. The reversal of 20280660 is 6608202.

It is a super-2 number, since 2×20280660² = 822610340071200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20280660.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20280661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60012 + ... + 60348.

It is an arithmetic number, because the mean of its divisors is an integer number (638820).

Almost surely, 2^20280660 is an apocalyptic number.

20280660 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 20280660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30663360).

20280660 is an abundant number, since it is smaller than the sum of its proper divisors (41046060).

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

20280660 is a wasteful number, since it uses less digits than its factorization.

20280660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425 (or 423 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20280660 is about 4503.4053781555. The cubic root of 20280660 is about 272.7055823154.

Adding to 20280660 its reverse (6608202), we get a palindrome (26888862).

The spelling of 20280660 in words is "twenty million, two hundred eighty thousand, six hundred sixty".