20181280 has 96 divisors (see below), whose sum is σ = 56077056. Its totient is φ = 6718464.

The previous prime is 20181247. The next prime is 20181311. The reversal of 20181280 is 8218102.

It is an unprimeable number.

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, 41197 + ... + 41683.

It is an arithmetic number, because the mean of its divisors is an integer number (584136).

Almost surely, 2^20181280 is an apocalyptic number.

20181280 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 20181280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28038528).

20181280 is an abundant number, since it is smaller than the sum of its proper divisors (35895776).

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

20181280 is a wasteful number, since it uses less digits than its factorization.

20181280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 20181280 is about 4492.3579554617. The cubic root of 20181280 is about 272.2594122605.

Adding to 20181280 its reverse (8218102), we get a palindrome (28399382).

The spelling of 20181280 in words is "twenty million, one hundred eighty-one thousand, two hundred eighty".