199018621 has 2 divisors, whose sum is σ = 199018622. Its totient is φ = 199018620.

The previous prime is 199018613. The next prime is 199018627. The reversal of 199018621 is 126810991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157879225 + 41139396 = 12565^2 + 6414^2 .

It is a cyclic number.

It is not a de Polignac number, because 199018621 - 2³ = 199018613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199018627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99509310 + 99509311.

It is an arithmetic number, because the mean of its divisors is an integer number (99509311).

Almost surely, 2^199018621 is an apocalyptic number.

It is an amenable number.

199018621 is a deficient number, since it is larger than the sum of its proper divisors (1).

199018621 is an equidigital number, since it uses as much as digits as its factorization.

199018621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 37.

The square root of 199018621 is about 14107.3959680729. The cubic root of 199018621 is about 583.8454556427.

The spelling of 199018621 in words is "one hundred ninety-nine million, eighteen thousand, six hundred twenty-one".