506191681 has 4 divisors (see below), whose sum is σ = 506236864. Its totient is φ = 506146500.

The previous prime is 506191669. The next prime is 506191691. The reversal of 506191681 is 186191605.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 506191681 - 2²³ = 497803073 is a prime.

It is a super-2 number, since 2×506191681² = 512460035827211522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 506191681.

It is not an unprimeable number, because it can be changed into a prime (506191661) 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, 8236 + ... + 32866.

It is an arithmetic number, because the mean of its divisors is an integer number (126559216).

Almost surely, 2^506191681 is an apocalyptic number.

It is an amenable number.

506191681 is a deficient number, since it is larger than the sum of its proper divisors (45183).

506191681 is a wasteful number, since it uses less digits than its factorization.

506191681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45182.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 506191681 is about 22498.7039848966. The cubic root of 506191681 is about 796.9633216697.

The spelling of 506191681 in words is "five hundred six million, one hundred ninety-one thousand, six hundred eighty-one".