121516181 has 2 divisors, whose sum is σ = 121516182. Its totient is φ = 121516180.

The previous prime is 121516159. The next prime is 121516211. The reversal of 121516181 is 181615121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85396081 + 36120100 = 9241^2 + 6010^2 .

It is an emirp because it is prime and its reverse (181615121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121516181 - 2¹⁰ = 121515157 is a prime.

It is a super-3 number, since 3×121516181³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121516181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121516111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60758090 + 60758091.

It is an arithmetic number, because the mean of its divisors is an integer number (60758091).

Almost surely, 2^121516181 is an apocalyptic number.

It is an amenable number.

121516181 is a deficient number, since it is larger than the sum of its proper divisors (1).

121516181 is an equidigital number, since it uses as much as digits as its factorization.

121516181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 26.

The square root of 121516181 is about 11023.4378031538. The cubic root of 121516181 is about 495.3110733890.

The spelling of 121516181 in words is "one hundred twenty-one million, five hundred sixteen thousand, one hundred eighty-one".