1366221 has 4 divisors (see below), whose sum is σ = 1821632. Its totient is φ = 910812.

The previous prime is 1366213. The next prime is 1366241. The reversal of 1366221 is 1226631.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1366221 - 2³ = 1366213 is a prime.

It is a D-number.

It is a Duffinian number.

1366221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1366241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227701 + ... + 227706.

It is an arithmetic number, because the mean of its divisors is an integer number (455408).

2^1366221 is an apocalyptic number.

It is an amenable number.

1366221 is a deficient number, since it is larger than the sum of its proper divisors (455411).

1366221 is an equidigital number, since it uses as much as digits as its factorization.

1366221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455410.

The product of its digits is 432, while the sum is 21.

The square root of 1366221 is about 1168.8545675147. The cubic root of 1366221 is about 110.9618406288.

The spelling of 1366221 in words is "one million, three hundred sixty-six thousand, two hundred twenty-one".