12218128162521 has 4 divisors (see below), whose sum is σ = 16290837550032. Its totient is φ = 8145418775012.

The previous prime is 12218128162519. The next prime is 12218128162619. The reversal of 12218128162521 is 12526182181221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12218128162521 - 2¹ = 12218128162519 is a prime.

It is a super-3 number, since 3×12218128162521³ (a number of 40 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (12218128162021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2036354693751 + ... + 2036354693756.

It is an arithmetic number, because the mean of its divisors is an integer number (4072709387508).

Almost surely, 2^{12218128162521} is an apocalyptic number.

It is an amenable number.

12218128162521 is a deficient number, since it is larger than the sum of its proper divisors (4072709387511).

12218128162521 is an equidigital number, since it uses as much as digits as its factorization.

12218128162521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4072709387510.

The product of its digits is 61440, while the sum is 42.

The spelling of 12218128162521 in words is "twelve trillion, two hundred eighteen billion, one hundred twenty-eight million, one hundred sixty-two thousand, five hundred twenty-one".