20557057 has 8 divisors (see below), whose sum is σ = 21019176. Its totient is φ = 20097792.

The previous prime is 20557051. The next prime is 20557067. The reversal of 20557057 is 75075502.

It can be written as a sum of positive squares in 4 ways, for example, as 11771761 + 8785296 = 3431^2 + 2964^2 .

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 20557057 - 2¹¹ = 20555009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20557051) 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 7 ways as a sum of consecutive naturals, for example, 20553 + ... + 21529.

It is an arithmetic number, because the mean of its divisors is an integer number (2627397).

Almost surely, 2^20557057 is an apocalyptic number.

It is an amenable number.

20557057 is a deficient number, since it is larger than the sum of its proper divisors (462119).

20557057 is an equidigital number, since it uses as much as digits as its factorization.

20557057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1427.

The product of its (nonzero) digits is 12250, while the sum is 31.

The square root of 20557057 is about 4533.9890824747. The cubic root of 20557057 is about 273.9388616321.

The spelling of 20557057 in words is "twenty million, five hundred fifty-seven thousand, fifty-seven".