199252721 has 2 divisors, whose sum is σ = 199252722. Its totient is φ = 199252720.

The previous prime is 199252709. The next prime is 199252723. The reversal of 199252721 is 127252991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198669025 + 583696 = 14095^2 + 764^2 .

It is an emirp because it is prime and its reverse (127252991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199252721 - 2¹⁸ = 198990577 is a prime.

Together with 199252723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199252723) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99626360 + 99626361.

It is an arithmetic number, because the mean of its divisors is an integer number (99626361).

Almost surely, 2^199252721 is an apocalyptic number.

It is an amenable number.

199252721 is a deficient number, since it is larger than the sum of its proper divisors (1).

199252721 is an equidigital number, since it uses as much as digits as its factorization.

199252721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 38.

The square root of 199252721 is about 14115.6905959291. The cubic root of 199252721 is about 584.0742862670.

The spelling of 199252721 in words is "one hundred ninety-nine million, two hundred fifty-two thousand, seven hundred twenty-one".