199331921 has 2 divisors, whose sum is σ = 199331922. Its totient is φ = 199331920.

The previous prime is 199331917. The next prime is 199331927. The reversal of 199331921 is 129133991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199120321 + 211600 = 14111^2 + 460^2 .

It is a cyclic number.

It is not a de Polignac number, because 199331921 - 2² = 199331917 is a prime.

It is not a weakly prime, because it can be changed into another prime (199331927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99665960 + 99665961.

It is an arithmetic number, because the mean of its divisors is an integer number (99665961).

Almost surely, 2^199331921 is an apocalyptic number.

It is an amenable number.

199331921 is a deficient number, since it is larger than the sum of its proper divisors (1).

199331921 is an equidigital number, since it uses as much as digits as its factorization.

199331921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13122, while the sum is 38.

The square root of 199331921 is about 14118.4957059879. The cubic root of 199331921 is about 584.1516629699.

The spelling of 199331921 in words is "one hundred ninety-nine million, three hundred thirty-one thousand, nine hundred twenty-one".