199815923 has 2 divisors, whose sum is σ = 199815924. Its totient is φ = 199815922.

The previous prime is 199815893. The next prime is 199815929. The reversal of 199815923 is 329518991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199815923 - 2¹⁰ = 199814899 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (199815929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99907961 + 99907962.

It is an arithmetic number, because the mean of its divisors is an integer number (99907962).

Almost surely, 2^199815923 is an apocalyptic number.

199815923 is a deficient number, since it is larger than the sum of its proper divisors (1).

199815923 is an equidigital number, since it uses as much as digits as its factorization.

199815923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174960, while the sum is 47.

The square root of 199815923 is about 14135.6260208029. The cubic root of 199815923 is about 584.6240777664.

The spelling of 199815923 in words is "one hundred ninety-nine million, eight hundred fifteen thousand, nine hundred twenty-three".