1212309 has 18 divisors (see below), whose sum is σ = 2037750. Its totient is φ = 692496.

The previous prime is 1212301. The next prime is 1212319. The reversal of 1212309 is 9032121.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 815409 + 396900 = 903^2 + 630^2 .

It is not a de Polignac number, because 1212309 - 2³ = 1212301 is a prime.

It is a super-2 number, since 2×1212309² = 2939386222962, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1212291 and 1212300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 934 + ... + 1815.

2^1212309 is an apocalyptic number.

It is an amenable number.

1212309 is a deficient number, since it is larger than the sum of its proper divisors (825441).

1212309 is a wasteful number, since it uses less digits than its factorization.

1212309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2769 (or 2759 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 1212309 is about 1101.0490452291. The cubic root of 1212309 is about 106.6279623032.

Subtracting from 1212309 its product of nonzero digits (108), we obtain a square (1212201 = 1101²).

It can be divided in two parts, 1212 and 309, that added together give a square (1521 = 39²).

The spelling of 1212309 in words is "one million, two hundred twelve thousand, three hundred nine".