121999961 has 2 divisors, whose sum is σ = 121999962. Its totient is φ = 121999960.

The previous prime is 121999951. The next prime is 121999963. The reversal of 121999961 is 169999121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85470025 + 36529936 = 9245^2 + 6044^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121999961 is a prime.

It is a Sophie Germain prime.

Together with 121999963, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (121999963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60999980 + 60999981.

It is an arithmetic number, because the mean of its divisors is an integer number (60999981).

Almost surely, 2^121999961 is an apocalyptic number.

It is an amenable number.

121999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

121999961 is an equidigital number, since it uses as much as digits as its factorization.

121999961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 78732, while the sum is 47.

The square root of 121999961 is about 11045.3592517401. The cubic root of 121999961 is about 495.9675135352.

The spelling of 121999961 in words is "one hundred twenty-one million, nine hundred ninety-nine thousand, nine hundred sixty-one".