663791 has 6 divisors (see below), whose sum is σ = 681480. Its totient is φ = 646548.

The previous prime is 663787. The next prime is 663797. The reversal of 663791 is 197366.

663791 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 663791 - 2² = 663787 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 (663797) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1670 + ... + 2028.

It is an arithmetic number, because the mean of its divisors is an integer number (113580).

2⁶⁶³⁷⁹¹ is an apocalyptic number.

663791 is a deficient number, since it is larger than the sum of its proper divisors (17689).

663791 is an equidigital number, since it uses as much as digits as its factorization.

663791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445 (or 402 counting only the distinct ones).

The product of its digits is 6804, while the sum is 32.

The square root of 663791 is about 814.7336988243. The cubic root of 663791 is about 87.2322591275.

The spelling of 663791 in words is "six hundred sixty-three thousand, seven hundred ninety-one".