523991 has 8 divisors (see below), whose sum is σ = 597744. Its totient is φ = 455040.

The previous prime is 523987. The next prime is 523997. The reversal of 523991 is 199325.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 523991 - 2² = 523987 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 (523997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 965 + ... + 1406.

It is an arithmetic number, because the mean of its divisors is an integer number (74718).

2⁵²³⁹⁹¹ is an apocalyptic number.

523991 is a deficient number, since it is larger than the sum of its proper divisors (73753).

523991 is a wasteful number, since it uses less digits than its factorization.

523991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2401.

The product of its digits is 2430, while the sum is 29.

The square root of 523991 is about 723.8722262941. The cubic root of 523991 is about 80.6197182206.

The spelling of 523991 in words is "five hundred twenty-three thousand, nine hundred ninety-one".