1231909 has 12 divisors (see below), whose sum is σ = 1481088. Its totient is φ = 1020600.

The previous prime is 1231889. The next prime is 1231943. The reversal of 1231909 is 9091321.

It is not a de Polignac number, because 1231909 - 2⁵ = 1231877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231999) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1114 + ... + 1924.

It is an arithmetic number, because the mean of its divisors is an integer number (123424).

2^1231909 is an apocalyptic number.

It is an amenable number.

1231909 is a deficient number, since it is larger than the sum of its proper divisors (249179).

1231909 is an equidigital number, since it uses as much as digits as its factorization.

1231909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856 (or 849 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 1231909 is about 1109.9139606294. The cubic root of 1231909 is about 107.1995287070.

The spelling of 1231909 in words is "one million, two hundred thirty-one thousand, nine hundred nine".