199899421 has 2 divisors, whose sum is σ = 199899422. Its totient is φ = 199899420.

The previous prime is 199899383. The next prime is 199899431. The reversal of 199899421 is 124998991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107931321 + 91968100 = 10389^2 + 9590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199899421 is a prime.

It is a super-2 number, since 2×199899421² = 79919557032270482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199899431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99949710 + 99949711.

It is an arithmetic number, because the mean of its divisors is an integer number (99949711).

Almost surely, 2^199899421 is an apocalyptic number.

It is an amenable number.

199899421 is a deficient number, since it is larger than the sum of its proper divisors (1).

199899421 is an equidigital number, since it uses as much as digits as its factorization.

199899421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 419904, while the sum is 52.

The square root of 199899421 is about 14138.5791718970. The cubic root of 199899421 is about 584.7054996114.

The spelling of 199899421 in words is "one hundred ninety-nine million, eight hundred ninety-nine thousand, four hundred twenty-one".