1331393221 has 2 divisors, whose sum is σ = 1331393222. Its totient is φ = 1331393220.

The previous prime is 1331393171. The next prime is 1331393227. The reversal of 1331393221 is 1223931331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 871076196 + 460317025 = 29514^2 + 21455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331393221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1331393221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331393227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665696610 + 665696611.

It is an arithmetic number, because the mean of its divisors is an integer number (665696611).

Almost surely, 2^1331393221 is an apocalyptic number.

It is an amenable number.

1331393221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331393221 is an equidigital number, since it uses as much as digits as its factorization.

1331393221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2916, while the sum is 28.

The square root of 1331393221 is about 36488.2614137753. The cubic root of 1331393221 is about 1100.1083146785.

The spelling of 1331393221 in words is "one billion, three hundred thirty-one million, three hundred ninety-three thousand, two hundred twenty-one".