199906457881 has 27 divisors (see below), whose sum is σ = 218840053887. Its totient is φ = 182527778160.

The previous prime is 199906457837. The next prime is 199906457887. The reversal of 199906457881 is 188754609991.

The square root of 199906457881 is 447109.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 29571961225 + 170334496656 = 171965^2 + 412716^2 .

It is not a de Polignac number, because 199906457881 - 2⁷ = 199906457753 is a prime.

It is a super-2 number, since 2×199906457881² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (199906457887) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 947423866 + ... + 947424076.

It is an arithmetic number, because the mean of its divisors is an integer number (8105187181).

Almost surely, 2^199906457881 is an apocalyptic number.

199906457881 is the 447109-th square number.

199906457881 is the 223555-th centered octagonal number.

It is an amenable number.

199906457881 is a deficient number, since it is larger than the sum of its proper divisors (18933596006).

199906457881 is an frugal number, since it uses more digits than its factorization.

199906457881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 774 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 67.

The spelling of 199906457881 in words is "one hundred ninety-nine billion, nine hundred six million, four hundred fifty-seven thousand, eight hundred eighty-one".