507991 has 4 divisors (see below), whose sum is σ = 554184. Its totient is φ = 461800.

The previous prime is 507979. The next prime is 508009. The reversal of 507991 is 199705.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-507991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (507901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23080 + ... + 23101.

It is an arithmetic number, because the mean of its divisors is an integer number (138546).

2⁵⁰⁷⁹⁹¹ is an apocalyptic number.

507991 is a deficient number, since it is larger than the sum of its proper divisors (46193).

507991 is a wasteful number, since it uses less digits than its factorization.

507991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46192.

The product of its (nonzero) digits is 2835, while the sum is 31.

The square root of 507991 is about 712.7348735680. The cubic root of 507991 is about 79.7906505547.

The spelling of 507991 in words is "five hundred seven thousand, nine hundred ninety-one".