28091457 has 6 divisors (see below), whose sum is σ = 40576562. Its totient is φ = 18727632.

The previous prime is 28091449. The next prime is 28091467. The reversal of 28091457 is 75419082.

It can be written as a sum of positive squares in only one way, i.e., 23386896 + 4704561 = 4836^2 + 2169^2 .

It is not a de Polignac number, because 28091457 - 2³ = 28091449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28091447) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1560628 + ... + 1560645.

Almost surely, 2^28091457 is an apocalyptic number.

It is an amenable number.

28091457 is a deficient number, since it is larger than the sum of its proper divisors (12485105).

28091457 is a wasteful number, since it uses less digits than its factorization.

28091457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3121279 (or 3121276 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 28091457 is about 5300.1374510478. The cubic root of 28091457 is about 303.9891537278.

The spelling of 28091457 in words is "twenty-eight million, ninety-one thousand, four hundred fifty-seven".