646416683978 has 16 divisors (see below), whose sum is σ = 1080218863080. Its totient is φ = 288058362816.

The previous prime is 646416683831. The next prime is 646416684013. The reversal of 646416683978 is 879386614646.

It can be written as a sum of positive squares in 4 ways, for example, as 411692906689 + 234723777289 = 641633^2 + 484483^2 .

It is a super-2 number, since 2×646416683978² (a number of 24 digits) contains 22 as substring.

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, 428657525 + ... + 428659032.

Almost surely, 2^646416683978 is an apocalyptic number.

646416683978 is a deficient number, since it is larger than the sum of its proper divisors (433802179102).

646416683978 is a wasteful number, since it uses less digits than its factorization.

646416683978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857316601.

The product of its digits is 250822656, while the sum is 68.

The spelling of 646416683978 in words is "six hundred forty-six billion, four hundred sixteen million, six hundred eighty-three thousand, nine hundred seventy-eight".