1320646381 has 2 divisors, whose sum is σ = 1320646382. Its totient is φ = 1320646380.

The previous prime is 1320646351. The next prime is 1320646391. The reversal of 1320646381 is 1836460231.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1151516356 + 169130025 = 33934^2 + 13005^2 .

It is a cyclic number.

It is not a de Polignac number, because 1320646381 - 2⁷ = 1320646253 is a prime.

It is a super-2 number, since 2×1320646381² = 3488213727296794322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1320646321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660323190 + 660323191.

It is an arithmetic number, because the mean of its divisors is an integer number (660323191).

Almost surely, 2^1320646381 is an apocalyptic number.

It is an amenable number.

1320646381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320646381 is an equidigital number, since it uses as much as digits as its factorization.

1320646381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 1320646381 is about 36340.6986861838. The cubic root of 1320646381 is about 1097.1403355479.

The spelling of 1320646381 in words is "one billion, three hundred twenty million, six hundred forty-six thousand, three hundred eighty-one".