199940551 has 2 divisors, whose sum is σ = 199940552. Its totient is φ = 199940550.

The previous prime is 199940549. The next prime is 199940561. The reversal of 199940551 is 155049991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199940551 - 2¹ = 199940549 is a prime.

Together with 199940549, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 199940498 and 199940507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199940561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99970275 + 99970276.

It is an arithmetic number, because the mean of its divisors is an integer number (99970276).

Almost surely, 2^199940551 is an apocalyptic number.

199940551 is a deficient number, since it is larger than the sum of its proper divisors (1).

199940551 is an equidigital number, since it uses as much as digits as its factorization.

199940551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72900, while the sum is 43.

The square root of 199940551 is about 14140.0336279657. The cubic root of 199940551 is about 584.7455985903.

The spelling of 199940551 in words is "one hundred ninety-nine million, nine hundred forty thousand, five hundred fifty-one".