28001281 has 32 divisors (see below), whose sum is σ = 37029888. Its totient is φ = 20528640.

The previous prime is 28001251. The next prime is 28001291. The reversal of 28001281 is 18210082.

It is not a de Polignac number, because 28001281 - 2⁵ = 28001249 is a prime.

It is a super-2 number, since 2×28001281² = 1568143475281922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28001201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 171706 + ... + 171868.

It is an arithmetic number, because the mean of its divisors is an integer number (1157184).

Almost surely, 2^28001281 is an apocalyptic number.

It is an amenable number.

28001281 is a deficient number, since it is larger than the sum of its proper divisors (9028607).

28001281 is a wasteful number, since it uses less digits than its factorization.

28001281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301.

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

The square root of 28001281 is about 5291.6236638673. The cubic root of 28001281 is about 303.6635279151.

It can be divided in two parts, 28001 and 281, that added together give a palindrome (28282).

The spelling of 28001281 in words is "twenty-eight million, one thousand, two hundred eighty-one".