1366781 has 4 divisors (see below), whose sum is σ = 1471932. Its totient is φ = 1261632.

The previous prime is 1366769. The next prime is 1366793. The reversal of 1366781 is 1876631.

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

It is an interprime number because it is at equal distance from previous prime (1366769) and next prime (1366793).

It can be written as a sum of positive squares in 2 ways, for example, as 136900 + 1229881 = 370^2 + 1109^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1366781 is a prime.

It is a super-2 number, since 2×1366781² = 3736180603922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1366721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52556 + ... + 52581.

It is an arithmetic number, because the mean of its divisors is an integer number (367983).

2^1366781 is an apocalyptic number.

It is an amenable number.

1366781 is a deficient number, since it is larger than the sum of its proper divisors (105151).

1366781 is a wasteful number, since it uses less digits than its factorization.

1366781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105150.

The product of its digits is 6048, while the sum is 32.

The square root of 1366781 is about 1169.0940937324. The cubic root of 1366781 is about 110.9769992653.

The spelling of 1366781 in words is "one million, three hundred sixty-six thousand, seven hundred eighty-one".