199451681 has 16 divisors (see below), whose sum is σ = 236277888. Its totient is φ = 167357520.

The previous prime is 199451671. The next prime is 199451687. The reversal of 199451681 is 186154991.

It is not a de Polignac number, because 199451681 - 2⁶ = 199451617 is a prime.

It is a super-3 number, since 3×199451681³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199451687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11540 + ... + 23066.

It is an arithmetic number, because the mean of its divisors is an integer number (14767368).

Almost surely, 2^199451681 is an apocalyptic number.

199451681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

199451681 is a deficient number, since it is larger than the sum of its proper divisors (36826207).

199451681 is a wasteful number, since it uses less digits than its factorization.

199451681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11573 (or 11551 counting only the distinct ones).

The product of its digits is 77760, while the sum is 44.

The square root of 199451681 is about 14122.7363141850. The cubic root of 199451681 is about 584.2686270050.

The spelling of 199451681 in words is "one hundred ninety-nine million, four hundred fifty-one thousand, six hundred eighty-one".