1366021 has 2 divisors, whose sum is σ = 1366022. Its totient is φ = 1366020.

The previous prime is 1366019. The next prime is 1366031. The reversal of 1366021 is 1206631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 748225 + 617796 = 865^2 + 786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1366021 - 2¹ = 1366019 is a prime.

Together with 1366019, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1366021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1366031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 683010 + 683011.

It is an arithmetic number, because the mean of its divisors is an integer number (683011).

2^1366021 is an apocalyptic number.

It is an amenable number.

1366021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1366021 is an equidigital number, since it uses as much as digits as its factorization.

1366021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 1366021 is about 1168.7690105406. The cubic root of 1366021 is about 110.9564258262.

The spelling of 1366021 in words is "one million, three hundred sixty-six thousand, twenty-one".