505918681 has 4 divisors (see below), whose sum is σ = 532546000. Its totient is φ = 479291364.

The previous prime is 505918663. The next prime is 505918697. The reversal of 505918681 is 186819505.

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: 186819505 = 5 ⋅37363901.

It is a cyclic number.

It is not a de Polignac number, because 505918681 - 2⁹ = 505918169 is a prime.

It is a super-2 number, since 2×505918681² = 511907423569559522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (505918081) 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, 13313631 + ... + 13313668.

It is an arithmetic number, because the mean of its divisors is an integer number (133136500).

Almost surely, 2^505918681 is an apocalyptic number.

It is an amenable number.

505918681 is a deficient number, since it is larger than the sum of its proper divisors (26627319).

505918681 is a wasteful number, since it uses less digits than its factorization.

505918681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26627318.

The product of its (nonzero) digits is 86400, while the sum is 43.

The square root of 505918681 is about 22492.6361505271. The cubic root of 505918681 is about 796.8200227836.

The spelling of 505918681 in words is "five hundred five million, nine hundred eighteen thousand, six hundred eighty-one".