199355985421 has 2 divisors, whose sum is σ = 199355985422. Its totient is φ = 199355985420.

The previous prime is 199355985341. The next prime is 199355985461. The reversal of 199355985421 is 124589553991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116533476900 + 82822508521 = 341370^2 + 287789^2 .

It is a cyclic number.

It is not a de Polignac number, because 199355985421 - 2⁹ = 199355984909 is a prime.

It is a super-4 number, since 4×199355985421⁴ (a number of 46 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 199355985421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199355985461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99677992710 + 99677992711.

It is an arithmetic number, because the mean of its divisors is an integer number (99677992711).

Almost surely, 2^199355985421 is an apocalyptic number.

It is an amenable number.

199355985421 is a deficient number, since it is larger than the sum of its proper divisors (1).

199355985421 is an equidigital number, since it uses as much as digits as its factorization.

199355985421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496000, while the sum is 61.

The spelling of 199355985421 in words is "one hundred ninety-nine billion, three hundred fifty-five million, nine hundred eighty-five thousand, four hundred twenty-one".