1366781243 has 4 divisors (see below), whose sum is σ = 1375166568. Its totient is φ = 1358395920.

The previous prime is 1366781237. The next prime is 1366781309. The reversal of 1366781243 is 3421876631.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1366781243 - 2⁶ = 1366781179 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1366781243.

It is not an unprimeable number, because it can be changed into a prime (1366781203) 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 in 3 ways as a sum of consecutive naturals, for example, 4192418 + ... + 4192743.

It is an arithmetic number, because the mean of its divisors is an integer number (343791642).

Almost surely, 2^1366781243 is an apocalyptic number.

1366781243 is a deficient number, since it is larger than the sum of its proper divisors (8385325).

1366781243 is an equidigital number, since it uses as much as digits as its factorization.

1366781243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8385324.

The product of its digits is 145152, while the sum is 41.

The square root of 1366781243 is about 36970.0046388961. The cubic root of 1366781243 is about 1109.7700584218.

The spelling of 1366781243 in words is "one billion, three hundred sixty-six million, seven hundred eighty-one thousand, two hundred forty-three".