20001280 has 80 divisors (see below), whose sum is σ = 51731064. Its totient is φ = 7372800.

The previous prime is 20001277. The next prime is 20001301. The reversal of 20001280 is 8210002.

It can be written as a sum of positive squares in 4 ways, for example, as 15872256 + 4129024 = 3984^2 + 2032^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 20001280.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32980 + ... + 33580.

Almost surely, 2^20001280 is an apocalyptic number.

20001280 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 20001280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25865532).

20001280 is an abundant number, since it is smaller than the sum of its proper divisors (31729784).

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

20001280 is an equidigital number, since it uses as much as digits as its factorization.

20001280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637 (or 621 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 20001280 is about 4472.2790610605. The cubic root of 20001280 is about 271.4475522935.

Adding to 20001280 its reverse (8210002), we get a palindrome (28211282).

It can be divided in two parts, 2000 and 1280, that multiplied together give a 4-th power (2560000 = 40⁴).

The spelling of 20001280 in words is "twenty million, one thousand, two hundred eighty".