199668561408 has 200 divisors, whose sum is σ = 608643981792. Its totient is φ = 65139462144.

The previous prime is 199668561401. The next prime is 199668561457. The reversal of 199668561408 is 804165866991.

199668561408 is a `hidden beast` number, since 1 + 9 + 9 + 6 + 6 + 8 + 5 + 614 + 0 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199668561401) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1897966 + ... + 2000402.

Almost surely, 2^199668561408 is an apocalyptic number.

199668561408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 199668561408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304321990896).

199668561408 is an abundant number, since it is smaller than the sum of its proper divisors (408975420384).

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

199668561408 is an equidigital number, since it uses as much as digits as its factorization.

199668561408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102514 (or 102489 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 63.

The spelling of 199668561408 in words is "one hundred ninety-nine billion, six hundred sixty-eight million, five hundred sixty-one thousand, four hundred eight".