1320399221 has 2 divisors, whose sum is σ = 1320399222. Its totient is φ = 1320399220.

The previous prime is 1320399193. The next prime is 1320399233. The reversal of 1320399221 is 1229930231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 900600100 + 419799121 = 30010^2 + 20489^2 .

It is a cyclic number.

It is not a de Polignac number, because 1320399221 - 2¹⁰ = 1320398197 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1320399251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660199610 + 660199611.

It is an arithmetic number, because the mean of its divisors is an integer number (660199611).

Almost surely, 2^1320399221 is an apocalyptic number.

It is an amenable number.

1320399221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320399221 is an equidigital number, since it uses as much as digits as its factorization.

1320399221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 1320399221 is about 36337.2979320147. The cubic root of 1320399221 is about 1097.0718877213.

The spelling of 1320399221 in words is "one billion, three hundred twenty million, three hundred ninety-nine thousand, two hundred twenty-one".