28297557 has 6 divisors (see below), whose sum is σ = 40874262. Its totient is φ = 18865032.

The previous prime is 28297463. The next prime is 28297559. The reversal of 28297557 is 75579282.

It is a happy number.

28297557 is a `hidden beast` number, since 2 + 8 + 2 + 97 + 557 = 666.

It can be written as a sum of positive squares in only one way, i.e., 23126481 + 5171076 = 4809^2 + 2274^2 .

It is not a de Polignac number, because 28297557 - 2¹⁴ = 28281173 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28297559) 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, 1572078 + ... + 1572095.

It is an arithmetic number, because the mean of its divisors is an integer number (6812377).

Almost surely, 2^28297557 is an apocalyptic number.

It is an amenable number.

28297557 is a deficient number, since it is larger than the sum of its proper divisors (12576705).

28297557 is a wasteful number, since it uses less digits than its factorization.

28297557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3144179 (or 3144176 counting only the distinct ones).

The product of its digits is 352800, while the sum is 45.

The square root of 28297557 is about 5319.5448113537. The cubic root of 28297557 is about 304.7307737984.

The spelling of 28297557 in words is "twenty-eight million, two hundred ninety-seven thousand, five hundred fifty-seven".