111521404212121 has 16 divisors (see below), whose sum is σ = 121284516139776. Its totient is φ = 102114728891136.

The previous prime is 111521404212073. The next prime is 111521404212133. The reversal of 111521404212121 is 121212404125111.

It is a cyclic number.

It is not a de Polignac number, because 111521404212121 - 2²⁹ = 111520867341209 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 111521404212121.

It is not an unprimeable number, because it can be changed into a prime (111521404212221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1943361 + ... + 15060526.

It is an arithmetic number, because the mean of its divisors is an integer number (7580282258736).

Almost surely, 2^{111521404212121} is an apocalyptic number.

It is an amenable number.

111521404212121 is a deficient number, since it is larger than the sum of its proper divisors (9763111927655).

111521404212121 is a wasteful number, since it uses less digits than its factorization.

111521404212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17014368.

The product of its (nonzero) digits is 1280, while the sum is 28.

Adding to 111521404212121 its reverse (121212404125111), we get a palindrome (232733808337232).

The spelling of 111521404212121 in words is "one hundred eleven trillion, five hundred twenty-one billion, four hundred four million, two hundred twelve thousand, one hundred twenty-one".