66111111615505 has 16 divisors (see below), whose sum is σ = 86556493323648. Its totient is φ = 48074676160000.

The previous prime is 66111111615407. The next prime is 66111111615517. The reversal of 66111111615505 is 50551611111166.

It is a happy number.

It is not a de Polignac number, because 66111111615505 - 2²³ = 66111103226897 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76218421 + ... + 77080930.

It is an arithmetic number, because the mean of its divisors is an integer number (5409780832728).

Almost surely, 2^{66111111615505} is an apocalyptic number.

It is an amenable number.

66111111615505 is a deficient number, since it is larger than the sum of its proper divisors (20445381708143).

66111111615505 is a wasteful number, since it uses less digits than its factorization.

66111111615505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153307208.

The product of its (nonzero) digits is 27000, while the sum is 40.

The spelling of 66111111615505 in words is "sixty-six trillion, one hundred eleven billion, one hundred eleven million, six hundred fifteen thousand, five hundred five".