646791 has 8 divisors (see below), whose sum is σ = 868224. Its totient is φ = 428280.

The previous prime is 646781. The next prime is 646823. The reversal of 646791 is 197646.

It is a happy number.

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

It is not a de Polignac number, because 646791 - 2¹⁹ = 122503 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646721) 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, 145 + ... + 1146.

It is an arithmetic number, because the mean of its divisors is an integer number (108528).

2⁶⁴⁶⁷⁹¹ is an apocalyptic number.

646791 is a deficient number, since it is larger than the sum of its proper divisors (221433).

646791 is a wasteful number, since it uses less digits than its factorization.

646791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461.

The product of its digits is 9072, while the sum is 33.

The square root of 646791 is about 804.2331751426. The cubic root of 646791 is about 86.4811234384.

The spelling of 646791 in words is "six hundred forty-six thousand, seven hundred ninety-one".