121531120555 has 64 divisors (see below), whose sum is σ = 164945289600. Its totient is φ = 85341634560.

The previous prime is 121531120517. The next prime is 121531120589. The reversal of 121531120555 is 555021135121.

It is not a de Polignac number, because 121531120555 - 2¹⁵ = 121531087787 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 36505131 + ... + 36508459.

It is an arithmetic number, because the mean of its divisors is an integer number (2577270150).

Almost surely, 2^121531120555 is an apocalyptic number.

121531120555 is a deficient number, since it is larger than the sum of its proper divisors (43414169045).

121531120555 is a wasteful number, since it uses less digits than its factorization.

121531120555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3664.

The product of its (nonzero) digits is 7500, while the sum is 31.

Adding to 121531120555 its reverse (555021135121), we get a palindrome (676552255676).

The spelling of 121531120555 in words is "one hundred twenty-one billion, five hundred thirty-one million, one hundred twenty thousand, five hundred fifty-five".