18728857 has 8 divisors (see below), whose sum is σ = 21625856. Its totient is φ = 15887232.

The previous prime is 18728839. The next prime is 18728861. The reversal of 18728857 is 75882781.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18728857 - 2⁷ = 18728729 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18729857) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13113 + ... + 14470.

It is an arithmetic number, because the mean of its divisors is an integer number (2703232).

Almost surely, 2^18728857 is an apocalyptic number.

It is an amenable number.

18728857 is a deficient number, since it is larger than the sum of its proper divisors (2896999).

18728857 is an equidigital number, since it uses as much as digits as its factorization.

18728857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27687.

The product of its digits is 250880, while the sum is 46.

The square root of 18728857 is about 4327.6849469433. The cubic root of 18728857 is about 265.5647478934.

The spelling of 18728857 in words is "eighteen million, seven hundred twenty-eight thousand, eight hundred fifty-seven".