1909649 has 4 divisors (see below), whose sum is σ = 2182464. Its totient is φ = 1636836.

The previous prime is 1909637. The next prime is 1909651. The reversal of 1909649 is 9469091.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9469091 = 61 ⋅155231.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1909649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1909619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136397 + ... + 136410.

It is an arithmetic number, because the mean of its divisors is an integer number (545616).

2^1909649 is an apocalyptic number.

It is an amenable number.

1909649 is a deficient number, since it is larger than the sum of its proper divisors (272815).

1909649 is an equidigital number, since it uses as much as digits as its factorization.

1909649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272814.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 1909649 is about 1381.9005029307. The cubic root of 1909649 is about 124.0655437394.

The spelling of 1909649 in words is "one million, nine hundred nine thousand, six hundred forty-nine".