12645647155661 has 8 divisors (see below), whose sum is σ = 13687518126744. Its totient is φ = 11613651739200.

The previous prime is 12645647155649. The next prime is 12645647155679. The reversal of 12645647155661 is 16655174654621.

It can be written as a sum of positive squares in 4 ways, for example, as 2152543794025 + 10493103361636 = 1467155^2 + 3239306^2 .

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 12645647155661 - 2²⁶ = 12645580046797 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 12645647155661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12645647151661) 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, 2468885990 + ... + 2468891111.

It is an arithmetic number, because the mean of its divisors is an integer number (1710939765843).

Almost surely, 2^{12645647155661} is an apocalyptic number.

It is an amenable number.

12645647155661 is a deficient number, since it is larger than the sum of its proper divisors (1041870971083).

12645647155661 is a wasteful number, since it uses less digits than its factorization.

12645647155661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4937777311.

The product of its digits is 36288000, while the sum is 59.

The spelling of 12645647155661 in words is "twelve trillion, six hundred forty-five billion, six hundred forty-seven million, one hundred fifty-five thousand, six hundred sixty-one".