1216729 has 2 divisors, whose sum is σ = 1216730. Its totient is φ = 1216728.

The previous prime is 1216717. The next prime is 1216751. The reversal of 1216729 is 9276121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 912025 + 304704 = 955^2 + 552^2 .

It is an emirp because it is prime and its reverse (9276121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1216729 - 2⁷ = 1216601 is a prime.

It is a Chen prime.

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

1216729 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1216697 and 1216706.

It is not a weakly prime, because it can be changed into another prime (1216759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608364 + 608365.

It is an arithmetic number, because the mean of its divisors is an integer number (608365).

2^1216729 is an apocalyptic number.

It is an amenable number.

1216729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216729 is an equidigital number, since it uses as much as digits as its factorization.

1216729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 28.

The square root of 1216729 is about 1103.0543957575. The cubic root of 1216729 is about 106.7573913458.

The spelling of 1216729 in words is "one million, two hundred sixteen thousand, seven hundred twenty-nine".