20005280 has 48 divisors (see below), whose sum is σ = 47786760. Its totient is φ = 7913472.

The previous prime is 20005259. The next prime is 20005289. The reversal of 20005280 is 8250002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18011536 + 1993744 = 4244^2 + 1412^2 .

It is a super-2 number, since 2×20005280² = 800422455756800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20005289) 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, 14876 + ... + 16164.

Almost surely, 2^20005280 is an apocalyptic number.

20005280 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 20005280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23893380).

20005280 is an abundant number, since it is smaller than the sum of its proper divisors (27781480).

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

20005280 is a wasteful number, since it uses less digits than its factorization.

20005280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1401 (or 1393 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 20005280 is about 4472.7262379895. The cubic root of 20005280 is about 271.4656464328.

Adding to 20005280 its reverse (8250002), we get a palindrome (28255282).

The spelling of 20005280 in words is "twenty million, five thousand, two hundred eighty".