646863791 has 8 divisors (see below), whose sum is σ = 741335040. Its totient is φ = 552908088.

The previous prime is 646863779. The next prime is 646863809. The reversal of 646863791 is 197368646.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646863791 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 (646863751) 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, 126191 + ... + 131216.

It is an arithmetic number, because the mean of its divisors is an integer number (92666880).

Almost surely, 2^646863791 is an apocalyptic number.

646863791 is a deficient number, since it is larger than the sum of its proper divisors (94471249).

646863791 is a wasteful number, since it uses less digits than its factorization.

646863791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257773.

The product of its digits is 1306368, while the sum is 50.

The square root of 646863791 is about 25433.5170788470. The cubic root of 646863791 is about 864.8436756274.

The spelling of 646863791 in words is "six hundred forty-six million, eight hundred sixty-three thousand, seven hundred ninety-one".