1220729 has 2 divisors, whose sum is σ = 1220730. Its totient is φ = 1220728.

The previous prime is 1220717. The next prime is 1220743. The reversal of 1220729 is 9270221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1081600 + 139129 = 1040^2 + 373^2 .

It is an emirp because it is prime and its reverse (9270221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1220729 - 2²⁰ = 172153 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1220029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610364 + 610365.

It is an arithmetic number, because the mean of its divisors is an integer number (610365).

2^1220729 is an apocalyptic number.

It is an amenable number.

1220729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220729 is an equidigital number, since it uses as much as digits as its factorization.

1220729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 1220729 is about 1104.8660552302. The cubic root of 1220729 is about 106.8742517873.

The spelling of 1220729 in words is "one million, two hundred twenty thousand, seven hundred twenty-nine".