15666115601001 has 4 divisors (see below), whose sum is σ = 20888154134672. Its totient is φ = 10444077067332.

The previous prime is 15666115600981. The next prime is 15666115601011. The reversal of 15666115601001 is 10010651166651.

15666115601001 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.

It is not a de Polignac number, because 15666115601001 - 2⁹ = 15666115600489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15666115601011) 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, 2611019266831 + ... + 2611019266836.

It is an arithmetic number, because the mean of its divisors is an integer number (5222038533668).

Almost surely, 2^{15666115601001} is an apocalyptic number.

It is an amenable number.

15666115601001 is a deficient number, since it is larger than the sum of its proper divisors (5222038533671).

15666115601001 is an equidigital number, since it uses as much as digits as its factorization.

15666115601001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5222038533670.

The product of its (nonzero) digits is 32400, while the sum is 39.

Adding to 15666115601001 its reverse (10010651166651), we get a palindrome (25676766767652).

The spelling of 15666115601001 in words is "fifteen trillion, six hundred sixty-six billion, one hundred fifteen million, six hundred one thousand, one".