1321779729 has 16 divisors (see below), whose sum is σ = 1769829248. Its totient is φ = 877468032.

The previous prime is 1321779727. The next prime is 1321779737. The reversal of 1321779729 is 9279771231.

It is not a de Polignac number, because 1321779729 - 2¹ = 1321779727 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1321779721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1325259 + ... + 1326255.

It is an arithmetic number, because the mean of its divisors is an integer number (110614328).

Almost surely, 2^1321779729 is an apocalyptic number.

It is an amenable number.

1321779729 is a deficient number, since it is larger than the sum of its proper divisors (448049519).

1321779729 is an equidigital number, since it uses as much as digits as its factorization.

1321779729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2424.

The product of its digits is 333396, while the sum is 48.

The square root of 1321779729 is about 36356.2887132336. The cubic root of 1321779729 is about 1097.4540925825.

The spelling of 1321779729 in words is "one billion, three hundred twenty-one million, seven hundred seventy-nine thousand, seven hundred twenty-nine".