199919897 has 2 divisors, whose sum is σ = 199919898. Its totient is φ = 199919896.

The previous prime is 199919879. The next prime is 199919903. The reversal of 199919897 is 798919991.

199919897 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with previous prime (199919879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 106584976 + 93334921 = 10324^2 + 9661^2 .

It is an emirp because it is prime and its reverse (798919991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199919897 - 2⁶ = 199919833 is a prime.

It is not a weakly prime, because it can be changed into another prime (199910897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99959948 + 99959949.

It is an arithmetic number, because the mean of its divisors is an integer number (99959949).

Almost surely, 2^199919897 is an apocalyptic number.

It is an amenable number.

199919897 is a deficient number, since it is larger than the sum of its proper divisors (1).

199919897 is an equidigital number, since it uses as much as digits as its factorization.

199919897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3306744, while the sum is 62.

The square root of 199919897 is about 14139.3032713780. The cubic root of 199919897 is about 584.7254630193.

The spelling of 199919897 in words is "one hundred ninety-nine million, nine hundred nineteen thousand, eight hundred ninety-seven".