12151561 has 4 divisors (see below), whose sum is σ = 12190212. Its totient is φ = 12112912.

The previous prime is 12151553. The next prime is 12151603. The reversal of 12151561 is 16515121.

It is a happy number.

12151561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16515121 = 7 ⋅2359303.

It can be written as a sum of positive squares in 2 ways, for example, as 3920400 + 8231161 = 1980^2 + 2869^2 .

It is a cyclic number.

It is not a de Polignac number, because 12151561 - 2³ = 12151553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12151501) 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, 18850 + ... + 19483.

It is an arithmetic number, because the mean of its divisors is an integer number (3047553).

Almost surely, 2^12151561 is an apocalyptic number.

It is an amenable number.

12151561 is a deficient number, since it is larger than the sum of its proper divisors (38651).

12151561 is an equidigital number, since it uses as much as digits as its factorization.

12151561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38650.

The product of its digits is 300, while the sum is 22.

The square root of 12151561 is about 3485.9089202101. The cubic root of 12151561 is about 229.9026746382.

Adding to 12151561 its reverse (16515121), we get a palindrome (28666682).

The spelling of 12151561 in words is "twelve million, one hundred fifty-one thousand, five hundred sixty-one".