646667880394 has 8 divisors (see below), whose sum is σ = 1027060751268. Its totient is φ = 304314296640.

The previous prime is 646667880379. The next prime is 646667880401. The reversal of 646667880394 is 493088766646.

It can be written as a sum of positive squares in 2 ways, for example, as 641048429025 + 5619451369 = 800655^2 + 74963^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9509821737 + ... + 9509821804.

Almost surely, 2^646667880394 is an apocalyptic number.

646667880394 is a deficient number, since it is larger than the sum of its proper divisors (380392870874).

646667880394 is a wasteful number, since it uses less digits than its factorization.

646667880394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19019643560.

The product of its (nonzero) digits is 250822656, while the sum is 67.

The spelling of 646667880394 in words is "six hundred forty-six billion, six hundred sixty-seven million, eight hundred eighty thousand, three hundred ninety-four".