646856807 has 4 divisors (see below), whose sum is σ = 674981040. Its totient is φ = 618732576.

The previous prime is 646856801. The next prime is 646856831. The reversal of 646856807 is 708658646.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646856807 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 (646856801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14062082 + ... + 14062127.

It is an arithmetic number, because the mean of its divisors is an integer number (168745260).

Almost surely, 2^646856807 is an apocalyptic number.

646856807 is a deficient number, since it is larger than the sum of its proper divisors (28124233).

646856807 is a wasteful number, since it uses less digits than its factorization.

646856807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28124232.

The product of its (nonzero) digits is 1935360, while the sum is 50.

The square root of 646856807 is about 25433.3797793372. The cubic root of 646856807 is about 864.8405631278.

The spelling of 646856807 in words is "six hundred forty-six million, eight hundred fifty-six thousand, eight hundred seven".