1216640609 has 2 divisors, whose sum is σ = 1216640610. Its totient is φ = 1216640608.

The previous prime is 1216640587. The next prime is 1216640617. The reversal of 1216640609 is 9060466121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1080568384 + 136072225 = 32872^2 + 11665^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216640609 - 2²⁰ = 1215592033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1216645609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608320304 + 608320305.

It is an arithmetic number, because the mean of its divisors is an integer number (608320305).

Almost surely, 2^1216640609 is an apocalyptic number.

It is an amenable number.

1216640609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216640609 is an equidigital number, since it uses as much as digits as its factorization.

1216640609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 1216640609 is about 34880.3757003849. The cubic root of 1216640609 is about 1067.5480610260.

The spelling of 1216640609 in words is "one billion, two hundred sixteen million, six hundred forty thousand, six hundred nine".