121216999 has 2 divisors, whose sum is σ = 121217000. Its totient is φ = 121216998.

The previous prime is 121216981. The next prime is 121217009. The reversal of 121216999 is 999612121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121216999 - 2¹³ = 121208807 is a prime.

It is a super-3 number, since 3×121216999³ (a number of 25 digits) contains 333 as substring.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121216939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60608499 + 60608500.

It is an arithmetic number, because the mean of its divisors is an integer number (60608500).

Almost surely, 2^121216999 is an apocalyptic number.

121216999 is a deficient number, since it is larger than the sum of its proper divisors (1).

121216999 is an equidigital number, since it uses as much as digits as its factorization.

121216999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 40.

The square root of 121216999 is about 11009.8591725780. The cubic root of 121216999 is about 494.9042415861.

The spelling of 121216999 in words is "one hundred twenty-one million, two hundred sixteen thousand, nine hundred ninety-nine".