12601640561 has 4 divisors (see below), whose sum is σ = 12601865124. Its totient is φ = 12601416000.

The previous prime is 12601640543. The next prime is 12601640593. The reversal of 12601640561 is 16504610621.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16504610621 = 12527 ⋅1317523.

It can be written as a sum of positive squares in 2 ways, for example, as 10360186225 + 2241454336 = 101785^2 + 47344^2 .

It is a cyclic number.

It is not a de Polignac number, because 12601640561 - 2⁶ = 12601640497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12601645561) 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, 52661 + ... + 167261.

It is an arithmetic number, because the mean of its divisors is an integer number (3150466281).

Almost surely, 2^12601640561 is an apocalyptic number.

It is an amenable number.

12601640561 is a deficient number, since it is larger than the sum of its proper divisors (224563).

12601640561 is a wasteful number, since it uses less digits than its factorization.

12601640561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224562.

The product of its (nonzero) digits is 8640, while the sum is 32.

The spelling of 12601640561 in words is "twelve billion, six hundred one million, six hundred forty thousand, five hundred sixty-one".