20171557 has 8 divisors (see below), whose sum is σ = 23101632. Its totient is φ = 17253600.

The previous prime is 20171551. The next prime is 20171603. The reversal of 20171557 is 75517102.

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

It is not a de Polignac number, because 20171557 - 2¹¹ = 20169509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20171551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 882 + ... + 6412.

It is an arithmetic number, because the mean of its divisors is an integer number (2887704).

Almost surely, 2^20171557 is an apocalyptic number.

It is an amenable number.

20171557 is a deficient number, since it is larger than the sum of its proper divisors (2930075).

20171557 is an equidigital number, since it uses as much as digits as its factorization.

20171557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6059.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 20171557 is about 4491.2756539763. The cubic root of 20171557 is about 272.2156819074.

Adding to 20171557 its reverse (75517102), we get a palindrome (95688659).

The spelling of 20171557 in words is "twenty million, one hundred seventy-one thousand, five hundred fifty-seven".