209148911 has 2 divisors, whose sum is σ = 209148912. Its totient is φ = 209148910.

The previous prime is 209148871. The next prime is 209148917. The reversal of 209148911 is 119841902.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209148911 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209148917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104574455 + 104574456.

It is an arithmetic number, because the mean of its divisors is an integer number (104574456).

Almost surely, 2^209148911 is an apocalyptic number.

209148911 is a deficient number, since it is larger than the sum of its proper divisors (1).

209148911 is an equidigital number, since it uses as much as digits as its factorization.

209148911 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 209148911 is about 14461.9815723849. The cubic root of 209148911 is about 593.5881228734.

The spelling of 209148911 in words is "two hundred nine million, one hundred forty-eight thousand, nine hundred eleven".