199686461778 has 12 divisors (see below), whose sum is σ = 432654000558. Its totient is φ = 66562153920.

The previous prime is 199686461731. The next prime is 199686461789. The reversal of 199686461778 is 877164686991.

199686461778 is a `hidden beast` number, since 1 + 9 + 96 + 8 + 6 + 461 + 7 + 78 = 666.

It can be written as a sum of positive squares in only one way, i.e., 167791002129 + 31895459649 = 409623^2 + 178593^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5546846143 + ... + 5546846178.

Almost surely, 2^199686461778 is an apocalyptic number.

199686461778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

199686461778 is an abundant number, since it is smaller than the sum of its proper divisors (232967538780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

199686461778 is a wasteful number, since it uses less digits than its factorization.

199686461778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11093692329 (or 11093692326 counting only the distinct ones).

The product of its digits is 219469824, while the sum is 72.

The spelling of 199686461778 in words is "one hundred ninety-nine billion, six hundred eighty-six million, four hundred sixty-one thousand, seven hundred seventy-eight".