12345666654321 has 192 divisors, whose sum is σ = 25238754293760. Its totient is φ = 5759982731520.

The previous prime is 12345666654311. The next prime is 12345666654331.

12345666654321 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (12345666654311) and next prime (12345666654331).

It is not a de Polignac number, because 12345666654321 - 2⁵ = 12345666654289 is a prime.

It is a super-2 number, since 2×12345666654321² (a number of 27 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12345666654301) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 36833130 + ... + 37166796.

It is an arithmetic number, because the mean of its divisors is an integer number (131451845280).

Almost surely, 2^{12345666654321} is an apocalyptic number.

12345666654321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12345666654321 is an abundant number, since it is smaller than the sum of its proper divisors (12893087639439).

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

12345666654321 is a wasteful number, since it uses less digits than its factorization.

12345666654321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333781 (or 333738 counting only the distinct ones).

The product of its digits is 18662400, while the sum is 54.

It can be divided in two parts, 1234566 and 6654321, that added together give a palindrome (7888887).

The spelling of 12345666654321 in words is "twelve trillion, three hundred forty-five billion, six hundred sixty-six million, six hundred fifty-four thousand, three hundred twenty-one".