199621091 has 2 divisors, whose sum is σ = 199621092. Its totient is φ = 199621090.

The previous prime is 199621069. The next prime is 199621129. The reversal of 199621091 is 190126991.

It is an a-pointer prime, because the next prime (199621129) can be obtained adding 199621091 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199621091 - 2⁶ = 199621027 is a prime.

It is not a weakly prime, because it can be changed into another prime (199621001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99810545 + 99810546.

It is an arithmetic number, because the mean of its divisors is an integer number (99810546).

Almost surely, 2^199621091 is an apocalyptic number.

199621091 is a deficient number, since it is larger than the sum of its proper divisors (1).

199621091 is an equidigital number, since it uses as much as digits as its factorization.

199621091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8748, while the sum is 38.

The square root of 199621091 is about 14128.7328164984. The cubic root of 199621091 is about 584.4340019582.

The spelling of 199621091 in words is "one hundred ninety-nine million, six hundred twenty-one thousand, ninety-one".