28731057 has 4 divisors (see below), whose sum is σ = 38308080. Its totient is φ = 19154036.

The previous prime is 28731049. The next prime is 28731077. The reversal of 28731057 is 75013782.

28731057 is nontrivially palindromic in base 16.

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 28731057 - 2³ = 28731049 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28731047) 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, 4788507 + ... + 4788512.

It is an arithmetic number, because the mean of its divisors is an integer number (9577020).

Almost surely, 2^28731057 is an apocalyptic number.

It is an amenable number.

28731057 is a deficient number, since it is larger than the sum of its proper divisors (9577023).

28731057 is an equidigital number, since it uses as much as digits as its factorization.

28731057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9577022.

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 28731057 is about 5360.1359124560. The cubic root of 28731057 is about 306.2789864553.

The spelling of 28731057 in words is "twenty-eight million, seven hundred thirty-one thousand, fifty-seven".