15666511605051 has 4 divisors (see below), whose sum is σ = 20888682140072. Its totient is φ = 10444341070032.

The previous prime is 15666511605013. The next prime is 15666511605061. The reversal of 15666511605051 is 15050611566651.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 15666511605051 - 2⁷ = 15666511604923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15666511605061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2611085267506 + ... + 2611085267511.

It is an arithmetic number, because the mean of its divisors is an integer number (5222170535018).

Almost surely, 2^{15666511605051} is an apocalyptic number.

15666511605051 is a deficient number, since it is larger than the sum of its proper divisors (5222170535021).

15666511605051 is an equidigital number, since it uses as much as digits as its factorization.

15666511605051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5222170535020.

The product of its (nonzero) digits is 810000, while the sum is 48.

The spelling of 15666511605051 in words is "fifteen trillion, six hundred sixty-six billion, five hundred eleven million, six hundred five thousand, fifty-one".