505991331 has 36 divisors (see below), whose sum is σ = 771785664. Its totient is φ = 319111200.

The previous prime is 505991327. The next prime is 505991347. The reversal of 505991331 is 133199505.

505991331 is a `hidden beast` number, since 50 + 599 + 13 + 3 + 1 = 666.

It is not a de Polignac number, because 505991331 - 2² = 505991327 is a prime.

It is a super-2 number, since 2×505991331² = 512054454094303122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (505991351) 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 35 ways as a sum of consecutive naturals, for example, 615901 + ... + 616721.

Almost surely, 2^505991331 is an apocalyptic number.

505991331 is a deficient number, since it is larger than the sum of its proper divisors (265794333).

505991331 is a wasteful number, since it uses less digits than its factorization.

505991331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952 (or 902 counting only the distinct ones).

The product of its (nonzero) digits is 18225, while the sum is 36.

The square root of 505991331 is about 22494.2510655501. The cubic root of 505991331 is about 796.8581621171.

The spelling of 505991331 in words is "five hundred five million, nine hundred ninety-one thousand, three hundred thirty-one".