121171555521 has 12 divisors (see below), whose sum is σ = 175622940948. Its totient is φ = 80505332064.

The previous prime is 121171555501. The next prime is 121171555577. The reversal of 121171555521 is 125555171121.

121171555521 is a `hidden beast` number, since 1 + 2 + 11 + 71 + 5 + 55 + 521 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 53305574400 + 67865981121 = 230880^2 + 260511^2 .

It is not a de Polignac number, because 121171555521 - 2⁵ = 121171555489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121171555501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22972630 + ... + 22977903.

It is an arithmetic number, because the mean of its divisors is an integer number (14635245079).

Almost surely, 2^121171555521 is an apocalyptic number.

It is an amenable number.

121171555521 is a deficient number, since it is larger than the sum of its proper divisors (54451385427).

121171555521 is a wasteful number, since it uses less digits than its factorization.

121171555521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45950832 (or 45950829 counting only the distinct ones).

The product of its digits is 17500, while the sum is 36.

The spelling of 121171555521 in words is "one hundred twenty-one billion, one hundred seventy-one million, five hundred fifty-five thousand, five hundred twenty-one".