646790809 has 8 divisors (see below), whose sum is σ = 739398528. Its totient is φ = 554235360.

The previous prime is 646790801. The next prime is 646790813. The reversal of 646790809 is 908097646.

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

It is not a de Polignac number, because 646790809 - 2³ = 646790801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646790801) 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, 18564 + ... + 40474.

It is an arithmetic number, because the mean of its divisors is an integer number (92424816).

Almost surely, 2^646790809 is an apocalyptic number.

It is an amenable number.

646790809 is a deficient number, since it is larger than the sum of its proper divisors (92607719).

646790809 is a wasteful number, since it uses less digits than its factorization.

646790809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26135.

The product of its (nonzero) digits is 653184, while the sum is 49.

The square root of 646790809 is about 25432.0822780991. The cubic root of 646790809 is about 864.8111492564.

The spelling of 646790809 in words is "six hundred forty-six million, seven hundred ninety thousand, eight hundred nine".