20128857 has 24 divisors (see below), whose sum is σ = 31464000. Its totient is φ = 11412576.

The previous prime is 20128837. The next prime is 20128861. The reversal of 20128857 is 75882102.

It is not a de Polignac number, because 20128857 - 2⁶ = 20128793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20128837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21444 + ... + 22362.

It is an arithmetic number, because the mean of its divisors is an integer number (1311000).

Almost surely, 2^20128857 is an apocalyptic number.

It is an amenable number.

20128857 is a deficient number, since it is larger than the sum of its proper divisors (11335143).

20128857 is a wasteful number, since it uses less digits than its factorization.

20128857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1085 (or 1078 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 20128857 is about 4486.5194750497. The cubic root of 20128857 is about 272.0234670137.

The spelling of 20128857 in words is "twenty million, one hundred twenty-eight thousand, eight hundred fifty-seven".