646888439 has 4 divisors (see below), whose sum is σ = 667755840. Its totient is φ = 626021040.

The previous prime is 646888433. The next prime is 646888457. The reversal of 646888439 is 934888646.

It is a happy number.

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 646888439 - 2⁴ = 646888423 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 (646888433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10433654 + ... + 10433715.

It is an arithmetic number, because the mean of its divisors is an integer number (166938960).

Almost surely, 2^646888439 is an apocalyptic number.

646888439 is a deficient number, since it is larger than the sum of its proper divisors (20867401).

646888439 is a wasteful number, since it uses less digits than its factorization.

646888439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20867400.

The product of its digits is 7962624, while the sum is 56.

The square root of 646888439 is about 25434.0016316741. The cubic root of 646888439 is about 864.8546601121.

The spelling of 646888439 in words is "six hundred forty-six million, eight hundred eighty-eight thousand, four hundred thirty-nine".