121665566121 has 64 divisors (see below), whose sum is σ = 184316912640. Its totient is φ = 70711200000.

The previous prime is 121665566089. The next prime is 121665566123.

121665566121 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 121665566121 - 2⁵ = 121665566089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121665566123) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 165982671 + ... + 165983403.

It is an arithmetic number, because the mean of its divisors is an integer number (2879951760).

Almost surely, 2^121665566121 is an apocalyptic number.

121665566121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

121665566121 is a deficient number, since it is larger than the sum of its proper divisors (62651346519).

121665566121 is a wasteful number, since it uses less digits than its factorization.

121665566121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1718.

The product of its digits is 129600, while the sum is 42.

It can be divided in two parts, 121665 and 566121, that added together give a palindrome (687786).

The spelling of 121665566121 in words is "one hundred twenty-one billion, six hundred sixty-five million, five hundred sixty-six thousand, one hundred twenty-one".