12661654435221 has 8 divisors (see below), whose sum is σ = 18416951905824. Its totient is φ = 7673729960720.

The previous prime is 12661654435201. The next prime is 12661654435223. The reversal of 12661654435221 is 12253445616621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12661654435221 - 2²⁵ = 12661620880789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12661654435223) 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 7 ways as a sum of consecutive naturals, for example, 191843248986 + ... + 191843249051.

It is an arithmetic number, because the mean of its divisors is an integer number (2302118988228).

Almost surely, 2^{12661654435221} is an apocalyptic number.

12661654435221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12661654435221 is a deficient number, since it is larger than the sum of its proper divisors (5755297470603).

12661654435221 is a wasteful number, since it uses less digits than its factorization.

12661654435221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383686498051.

The product of its digits is 2073600, while the sum is 48.

The spelling of 12661654435221 in words is "twelve trillion, six hundred sixty-one billion, six hundred fifty-four million, four hundred thirty-five thousand, two hundred twenty-one".