28097291 has 4 divisors (see below), whose sum is σ = 28375584. Its totient is φ = 27819000.

The previous prime is 28097287. The next prime is 28097323. The reversal of 28097291 is 19279082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28097291 - 2² = 28097287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28097221) 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, 138995 + ... + 139196.

It is an arithmetic number, because the mean of its divisors is an integer number (7093896).

Almost surely, 2^28097291 is an apocalyptic number.

28097291 is a deficient number, since it is larger than the sum of its proper divisors (278293).

28097291 is a wasteful number, since it uses less digits than its factorization.

28097291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278292.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 28097291 is about 5300.6877855614. The cubic root of 28097291 is about 304.0101963051.

The spelling of 28097291 in words is "twenty-eight million, ninety-seven thousand, two hundred ninety-one".