199981261 has 4 divisors (see below), whose sum is σ = 204632032. Its totient is φ = 195330492.

The previous prime is 199981259. The next prime is 199981273. The reversal of 199981261 is 162189991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162189991 = 8191 ⋅19801.

It is a cyclic number.

It is not a de Polignac number, because 199981261 - 2¹ = 199981259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199981861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2325321 + ... + 2325406.

It is an arithmetic number, because the mean of its divisors is an integer number (51158008).

Almost surely, 2^199981261 is an apocalyptic number.

It is an amenable number.

199981261 is a deficient number, since it is larger than the sum of its proper divisors (4650771).

199981261 is an equidigital number, since it uses as much as digits as its factorization.

199981261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4650770.

The product of its digits is 69984, while the sum is 46.

The square root of 199981261 is about 14141.4730845128. The cubic root of 199981261 is about 584.7852826827.

The spelling of 199981261 in words is "one hundred ninety-nine million, nine hundred eighty-one thousand, two hundred sixty-one".