1321213409 has 2 divisors, whose sum is σ = 1321213410. Its totient is φ = 1321213408.

The previous prime is 1321213391. The next prime is 1321213417. The reversal of 1321213409 is 9043121231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1307545600 + 13667809 = 36160^2 + 3697^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321213409 - 2¹² = 1321209313 is a prime.

It is not a weakly prime, because it can be changed into another prime (1321213009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660606704 + 660606705.

It is an arithmetic number, because the mean of its divisors is an integer number (660606705).

Almost surely, 2^1321213409 is an apocalyptic number.

It is an amenable number.

1321213409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321213409 is an equidigital number, since it uses as much as digits as its factorization.

1321213409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 1321213409 is about 36348.4994050649. The cubic root of 1321213409 is about 1097.2973344955.

The spelling of 1321213409 in words is "one billion, three hundred twenty-one million, two hundred thirteen thousand, four hundred nine".