28091261 has 4 divisors (see below), whose sum is σ = 30645024. Its totient is φ = 25537500.

The previous prime is 28091249. The next prime is 28091279. The reversal of 28091261 is 16219082.

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 28091261 - 2⁶ = 28091197 is a prime.

It is a pancake number, because a pancake can be divided into 28091261 parts by 7495 straight cuts.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28091561) 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, 1276865 + ... + 1276886.

It is an arithmetic number, because the mean of its divisors is an integer number (7661256).

Almost surely, 2^28091261 is an apocalyptic number.

It is an amenable number.

28091261 is a deficient number, since it is larger than the sum of its proper divisors (2553763).

28091261 is a wasteful number, since it uses less digits than its factorization.

28091261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2553762.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 28091261 is about 5300.1189609291. The cubic root of 28091261 is about 303.9884467274.

The spelling of 28091261 in words is "twenty-eight million, ninety-one thousand, two hundred sixty-one".