646779605 has 8 divisors (see below), whose sum is σ = 802899000. Its totient is φ = 499581376.

The previous prime is 646779593. The next prime is 646779613. The reversal of 646779605 is 506977646.

It can be written as a sum of positive squares in 4 ways, for example, as 908209 + 645871396 = 953^2 + 25414^2 .

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

It is not a de Polignac number, because 646779605 - 2¹⁰ = 646778581 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2230130 + ... + 2230419.

It is an arithmetic number, because the mean of its divisors is an integer number (100362375).

Almost surely, 2^646779605 is an apocalyptic number.

It is an amenable number.

646779605 is a deficient number, since it is larger than the sum of its proper divisors (156119395).

646779605 is a wasteful number, since it uses less digits than its factorization.

646779605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4460583.

The product of its (nonzero) digits is 1905120, while the sum is 50.

The square root of 646779605 is about 25431.8620041868. The cubic root of 646779605 is about 864.8061556789.

The spelling of 646779605 in words is "six hundred forty-six million, seven hundred seventy-nine thousand, six hundred five".