199953991 has 2 divisors, whose sum is σ = 199953992. Its totient is φ = 199953990.

The previous prime is 199953961. The next prime is 199954021. The reversal of 199953991 is 199359991.

It is a balanced prime because it is at equal distance from previous prime (199953961) and next prime (199954021).

It is a cyclic number.

It is not a de Polignac number, because 199953991 - 2²³ = 191565383 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199953911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99976995 + 99976996.

It is an arithmetic number, because the mean of its divisors is an integer number (99976996).

Almost surely, 2^199953991 is an apocalyptic number.

199953991 is a deficient number, since it is larger than the sum of its proper divisors (1).

199953991 is an equidigital number, since it uses as much as digits as its factorization.

199953991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 885735, while the sum is 55.

The square root of 199953991 is about 14140.5088663739. The cubic root of 199953991 is about 584.7587004927.

The spelling of 199953991 in words is "one hundred ninety-nine million, nine hundred fifty-three thousand, nine hundred ninety-one".