12125404561 has 4 divisors (see below), whose sum is σ = 12132501300. Its totient is φ = 12118307824.

The previous prime is 12125404549. The next prime is 12125404583. The reversal of 12125404561 is 16540452121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16540452121 = 1361 ⋅12153161.

It can be written as a sum of positive squares in 2 ways, for example, as 3676118161 + 8449286400 = 60631^2 + 91920^2 .

It is a cyclic number.

It is not a de Polignac number, because 12125404561 - 2¹⁵ = 12125371793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12125404531) 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, 3545806 + ... + 3549223.

It is an arithmetic number, because the mean of its divisors is an integer number (3033125325).

Almost surely, 2^12125404561 is an apocalyptic number.

It is an amenable number.

12125404561 is a deficient number, since it is larger than the sum of its proper divisors (7096739).

12125404561 is an equidigital number, since it uses as much as digits as its factorization.

12125404561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7096738.

The product of its (nonzero) digits is 9600, while the sum is 31.

Adding to 12125404561 its reverse (16540452121), we get a palindrome (28665856682).

The spelling of 12125404561 in words is "twelve billion, one hundred twenty-five million, four hundred four thousand, five hundred sixty-one".