1909949 has 2 divisors, whose sum is σ = 1909950. Its totient is φ = 1909948.

The previous prime is 1909927. The next prime is 1909951. The reversal of 1909949 is 9499091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1909924 + 25 = 1382^2 + 5^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1909949 is a prime.

It is a Sophie Germain prime.

Together with 1909951, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1909909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954974 + 954975.

It is an arithmetic number, because the mean of its divisors is an integer number (954975).

2^1909949 is an apocalyptic number.

It is an amenable number.

1909949 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909949 is an equidigital number, since it uses as much as digits as its factorization.

1909949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26244, while the sum is 41.

The square root of 1909949 is about 1382.0090448329. The cubic root of 1909949 is about 124.0720401714.

The spelling of 1909949 in words is "one million, nine hundred nine thousand, nine hundred forty-nine".