1366221161 has 4 divisors (see below), whose sum is σ = 1366330500. Its totient is φ = 1366111824.

The previous prime is 1366221083. The next prime is 1366221179. The reversal of 1366221161 is 1611226631.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 293265625 + 1072955536 = 17125^2 + 32756^2 .

It is a cyclic number.

It is not a de Polignac number, because 1366221161 - 2³⁰ = 292479337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1366221191) 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, 33086 + ... + 61863.

It is an arithmetic number, because the mean of its divisors is an integer number (341582625).

Almost surely, 2^1366221161 is an apocalyptic number.

It is an amenable number.

1366221161 is a deficient number, since it is larger than the sum of its proper divisors (109339).

1366221161 is an equidigital number, since it uses as much as digits as its factorization.

1366221161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109338.

The product of its digits is 2592, while the sum is 29.

The square root of 1366221161 is about 36962.4290462626. The cubic root of 1366221161 is about 1109.6184498749.

Adding to 1366221161 its reverse (1611226631), we get a palindrome (2977447792).

The spelling of 1366221161 in words is "one billion, three hundred sixty-six million, two hundred twenty-one thousand, one hundred sixty-one".