121815488281 has 4 divisors (see below), whose sum is σ = 121852260532. Its totient is φ = 121778716032.

The previous prime is 121815488273. The next prime is 121815488299. The reversal of 121815488281 is 182884518121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182884518121 = 199 ⋅919017679.

It can be written as a sum of positive squares in 2 ways, for example, as 54529722256 + 67285766025 = 233516^2 + 259395^2 .

It is a cyclic number.

It is not a de Polignac number, because 121815488281 - 2³ = 121815488273 is a prime.

It is a super-2 number, since 2×121815488281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121815488231) 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 in 3 ways as a sum of consecutive naturals, for example, 18381156 + ... + 18387781.

It is an arithmetic number, because the mean of its divisors is an integer number (30463065133).

Almost surely, 2^121815488281 is an apocalyptic number.

It is an amenable number.

121815488281 is a deficient number, since it is larger than the sum of its proper divisors (36772251).

121815488281 is an equidigital number, since it uses as much as digits as its factorization.

121815488281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36772250.

The product of its digits is 327680, while the sum is 49.

The spelling of 121815488281 in words is "one hundred twenty-one billion, eight hundred fifteen million, four hundred eighty-eight thousand, two hundred eighty-one".