28723857 has 4 divisors (see below), whose sum is σ = 38298480. Its totient is φ = 19149236.

The previous prime is 28723853. The next prime is 28723867. The reversal of 28723857 is 75832782.

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 28723857 - 2² = 28723853 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28723853) 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, 4787307 + ... + 4787312.

It is an arithmetic number, because the mean of its divisors is an integer number (9574620).

Almost surely, 2^28723857 is an apocalyptic number.

It is an amenable number.

28723857 is a deficient number, since it is larger than the sum of its proper divisors (9574623).

28723857 is an equidigital number, since it uses as much as digits as its factorization.

28723857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9574622.

The product of its digits is 188160, while the sum is 42.

The square root of 28723857 is about 5359.4642456126. The cubic root of 28723857 is about 306.2533998234.

The spelling of 28723857 in words is "twenty-eight million, seven hundred twenty-three thousand, eight hundred fifty-seven".