491557 has 4 divisors (see below), whose sum is σ = 536256. Its totient is φ = 446860.

The previous prime is 491539. The next prime is 491581. The reversal of 491557 is 755194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 491557 - 2⁷ = 491429 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22333 + ... + 22354.

It is an arithmetic number, because the mean of its divisors is an integer number (134064).

2⁴⁹¹⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

491557 is a deficient number, since it is larger than the sum of its proper divisors (44699).

491557 is a wasteful number, since it uses less digits than its factorization.

491557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44698.

The product of its digits is 6300, while the sum is 31.

The square root of 491557 is about 701.1112607853. Note that the first 3 decimals coincide. The cubic root of 491557 is about 78.9207665773.

The spelling of 491557 in words is "four hundred ninety-one thousand, five hundred fifty-seven".