646520791 has 4 divisors (see below), whose sum is σ = 738880912. Its totient is φ = 554160672.

The previous prime is 646520789. The next prime is 646520807. The reversal of 646520791 is 197025646.

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

It is a cyclic number.

It is not a de Polignac number, because 646520791 - 2¹ = 646520789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646520701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46180050 + ... + 46180063.

It is an arithmetic number, because the mean of its divisors is an integer number (184720228).

Almost surely, 2^646520791 is an apocalyptic number.

646520791 is a deficient number, since it is larger than the sum of its proper divisors (92360121).

646520791 is an equidigital number, since it uses as much as digits as its factorization.

646520791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92360120.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 646520791 is about 25426.7731141803. The cubic root of 646520791 is about 864.6907872699.

The spelling of 646520791 in words is "six hundred forty-six million, five hundred twenty thousand, seven hundred ninety-one".