1366661 has 2 divisors, whose sum is σ = 1366662. Its totient is φ = 1366660.

The previous prime is 1366657. The next prime is 1366663. The reversal of 1366661 is 1666631.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1366561 + 100 = 1169^2 + 10^2 .

It is a cyclic number.

It is not a de Polignac number, because 1366661 - 2² = 1366657 is a prime.

Together with 1366663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1366663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 683330 + 683331.

It is an arithmetic number, because the mean of its divisors is an integer number (683331).

2^1366661 is an apocalyptic number.

It is an amenable number.

1366661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1366661 is an equidigital number, since it uses as much as digits as its factorization.

1366661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 1366661 is about 1169.0427708172. The cubic root of 1366661 is about 110.9737513347.

The spelling of 1366661 in words is "one million, three hundred sixty-six thousand, six hundred sixty-one".