1231709 has 2 divisors, whose sum is σ = 1231710. Its totient is φ = 1231708.

The previous prime is 1231697. The next prime is 1231721. The reversal of 1231709 is 9071321.

It is a balanced prime because it is at equal distance from previous prime (1231697) and next prime (1231721).

It can be written as a sum of positive squares in only one way, i.e., 727609 + 504100 = 853^2 + 710^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231709 - 2⁸ = 1231453 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615854 + 615855.

It is an arithmetic number, because the mean of its divisors is an integer number (615855).

2^1231709 is an apocalyptic number.

It is an amenable number.

1231709 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231709 is an equidigital number, since it uses as much as digits as its factorization.

1231709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 1231709 is about 1109.8238598985. The cubic root of 1231709 is about 107.1937271242.

The spelling of 1231709 in words is "one million, two hundred thirty-one thousand, seven hundred nine".