1231609 has 4 divisors (see below), whose sum is σ = 1244404. Its totient is φ = 1218816.

The previous prime is 1231597. The next prime is 1231613. The reversal of 1231609 is 9061321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 394384 + 837225 = 628^2 + 915^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231609 - 2⁵ = 1231577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1231609.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231669) 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, 6252 + ... + 6445.

It is an arithmetic number, because the mean of its divisors is an integer number (311101).

2^1231609 is an apocalyptic number.

It is an amenable number.

1231609 is a deficient number, since it is larger than the sum of its proper divisors (12795).

1231609 is an equidigital number, since it uses as much as digits as its factorization.

1231609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12794.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 1231609 is about 1109.7788067899. The cubic root of 1231609 is about 107.1908260973.

The spelling of 1231609 in words is "one million, two hundred thirty-one thousand, six hundred nine".