1320856309 has 2 divisors, whose sum is σ = 1320856310. Its totient is φ = 1320856308.

The previous prime is 1320856289. The next prime is 1320856333. The reversal of 1320856309 is 9036580231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 666775684 + 654080625 = 25822^2 + 25575^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1320856309 is a prime.

It is a super-2 number, since 2×1320856309² = 3489322778050206962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1320856349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660428154 + 660428155.

It is an arithmetic number, because the mean of its divisors is an integer number (660428155).

Almost surely, 2^1320856309 is an apocalyptic number.

It is an amenable number.

1320856309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320856309 is an equidigital number, since it uses as much as digits as its factorization.

1320856309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 1320856309 is about 36343.5869033314. The cubic root of 1320856309 is about 1097.1984657375.

The spelling of 1320856309 in words is "one billion, three hundred twenty million, eight hundred fifty-six thousand, three hundred nine".