28097281 has 4 divisors (see below), whose sum is σ = 28112832. Its totient is φ = 28081732.

The previous prime is 28097233. The next prime is 28097287. The reversal of 28097281 is 18279082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28097281 - 2⁹ = 28096769 is a prime.

It is a super-2 number, since 2×28097281² = 1578914399185922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28097281.

It is not an unprimeable number, because it can be changed into a prime (28097287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4645 + ... + 8818.

It is an arithmetic number, because the mean of its divisors is an integer number (7028208).

Almost surely, 2^28097281 is an apocalyptic number.

It is an amenable number.

28097281 is a deficient number, since it is larger than the sum of its proper divisors (15551).

28097281 is a wasteful number, since it uses less digits than its factorization.

28097281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15550.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 28097281 is about 5300.6868422875. The cubic root of 28097281 is about 304.0101602387.

The spelling of 28097281 in words is "twenty-eight million, ninety-seven thousand, two hundred eighty-one".