646927867 has 4 divisors (see below), whose sum is σ = 646994416. Its totient is φ = 646861320.

The previous prime is 646927817. The next prime is 646927891. The reversal of 646927867 is 768729646.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 768729646 = 2 ⋅384364823.

It is a cyclic number.

It is not a de Polignac number, because 646927867 - 2²⁷ = 512710139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646927817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15543 + ... + 39184.

It is an arithmetic number, because the mean of its divisors is an integer number (161748604).

Almost surely, 2^646927867 is an apocalyptic number.

646927867 is a deficient number, since it is larger than the sum of its proper divisors (66549).

646927867 is a wasteful number, since it uses less digits than its factorization.

646927867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66548.

The product of its digits is 6096384, while the sum is 55.

The square root of 646927867 is about 25434.7767240053. The cubic root of 646927867 is about 864.8722307857.

The spelling of 646927867 in words is "six hundred forty-six million, nine hundred twenty-seven thousand, eight hundred sixty-seven".