12640660121261 has 8 divisors (see below), whose sum is σ = 13306446698400. Its totient is φ = 11974922411760.

The previous prime is 12640660121231. The next prime is 12640660121279. The reversal of 12640660121261 is 16212106604621.

It is a happy number.

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 12640660121261 - 2⁶ = 12640660121197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12640660121231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11685350 + ... + 12721191.

It is an arithmetic number, because the mean of its divisors is an integer number (1663305837300).

Almost surely, 2^{12640660121261} is an apocalyptic number.

It is an amenable number.

12640660121261 is a deficient number, since it is larger than the sum of its proper divisors (665786577139).

12640660121261 is a wasteful number, since it uses less digits than its factorization.

12640660121261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24433819.

The product of its (nonzero) digits is 41472, while the sum is 38.

Adding to 12640660121261 its reverse (16212106604621), we get a palindrome (28852766725882).

The spelling of 12640660121261 in words is "twelve trillion, six hundred forty billion, six hundred sixty million, one hundred twenty-one thousand, two hundred sixty-one".