121665566120 has 64 divisors (see below), whose sum is σ = 313922286720. Its totient is φ = 41571512064.

The previous prime is 121665566089. The next prime is 121665566123. The reversal of 121665566120 is 21665566121.

It is not an unprimeable number, because it can be changed into a prime (121665566123) 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 15 ways as a sum of consecutive naturals, for example, 659462 + ... + 823541.

It is an arithmetic number, because the mean of its divisors is an integer number (4905035730).

Almost surely, 2^121665566120 is an apocalyptic number.

121665566120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121665566120 is an abundant number, since it is smaller than the sum of its proper divisors (192256720600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121665566120 is a wasteful number, since it uses less digits than its factorization.

121665566120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1483314 (or 1483310 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 41.

Subtracting from 121665566120 its reverse (21665566121), we obtain a palindrome (99999999999).

The spelling of 121665566120 in words is "one hundred twenty-one billion, six hundred sixty-five million, five hundred sixty-six thousand, one hundred twenty".