505640857 has 4 divisors (see below), whose sum is σ = 506092240. Its totient is φ = 505189476.

The previous prime is 505640831. The next prime is 505640867. The reversal of 505640857 is 758046505.

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, and also an emirpimes, since its reverse is a distinct semiprime: 758046505 = 5 ⋅151609301.

It is a cyclic number.

It is not a de Polignac number, because 505640857 - 2¹⁹ = 505116569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (505640867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224007 + ... + 226252.

It is an arithmetic number, because the mean of its divisors is an integer number (126523060).

Almost surely, 2^505640857 is an apocalyptic number.

It is an amenable number.

505640857 is a deficient number, since it is larger than the sum of its proper divisors (451383).

505640857 is a wasteful number, since it uses less digits than its factorization.

505640857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451382.

The product of its (nonzero) digits is 168000, while the sum is 40.

The square root of 505640857 is about 22486.4594145010. The cubic root of 505640857 is about 796.6741388242.

The spelling of 505640857 in words is "five hundred five million, six hundred forty thousand, eight hundred fifty-seven".