20557128 has 16 divisors (see below), whose sum is σ = 51392880. Its totient is φ = 6852368.

The previous prime is 20557099. The next prime is 20557129. The reversal of 20557128 is 82175502.

It is a junction number, because it is equal to n+sod(n) for n = 20557095 and 20557104.

It is not an unprimeable number, because it can be changed into a prime (20557129) 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, 428250 + ... + 428297.

It is an arithmetic number, because the mean of its divisors is an integer number (3212055).

Almost surely, 2^20557128 is an apocalyptic number.

It is an amenable number.

20557128 is an abundant number, since it is smaller than the sum of its proper divisors (30835752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20557128 is a wasteful number, since it uses less digits than its factorization.

20557128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856556 (or 856552 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 20557128 is about 4533.9969122177. The cubic root of 20557128 is about 273.9391770086.

The spelling of 20557128 in words is "twenty million, five hundred fifty-seven thousand, one hundred twenty-eight".