15666115601 has 4 divisors (see below), whose sum is σ = 15744840000. Its totient is φ = 15587391204.

The previous prime is 15666115541. The next prime is 15666115609. The reversal of 15666115601 is 10651166651.

15666115601 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 a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10651166651 = 31 ⋅343586021.

It is a cyclic number.

It is not a de Polignac number, because 15666115601 - 2⁶ = 15666115537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15666115609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39361901 + ... + 39362298.

It is an arithmetic number, because the mean of its divisors is an integer number (3936210000).

Almost surely, 2^15666115601 is an apocalyptic number.

It is an amenable number.

15666115601 is a deficient number, since it is larger than the sum of its proper divisors (78724399).

15666115601 is an equidigital number, since it uses as much as digits as its factorization.

15666115601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78724398.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 15666115601 in words is "fifteen billion, six hundred sixty-six million, one hundred fifteen thousand, six hundred one".