121668509 has 2 divisors, whose sum is σ = 121668510. Its totient is φ = 121668508.

The previous prime is 121668493. The next prime is 121668553. The reversal of 121668509 is 905866121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117787609 + 3880900 = 10853^2 + 1970^2 .

It is a cyclic number.

It is not a de Polignac number, because 121668509 - 2⁴ = 121668493 is a prime.

It is a Sophie Germain prime.

It is a Chen 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 (121667509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60834254 + 60834255.

It is an arithmetic number, because the mean of its divisors is an integer number (60834255).

Almost surely, 2^121668509 is an apocalyptic number.

It is an amenable number.

121668509 is a deficient number, since it is larger than the sum of its proper divisors (1).

121668509 is an equidigital number, since it uses as much as digits as its factorization.

121668509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 121668509 is about 11030.3449175445. The cubic root of 121668509 is about 495.5179545893.

The spelling of 121668509 in words is "one hundred twenty-one million, six hundred sixty-eight thousand, five hundred nine".