66555166665 has 32 divisors (see below), whose sum is σ = 114694151040. Its totient is φ = 32761483776.

The previous prime is 66555166661. The next prime is 66555166669. The reversal of 66555166665 is 56666155566.

It is an interprime number because it is at equal distance from previous prime (66555166661) and next prime (66555166669).

It is not a de Polignac number, because 66555166665 - 2² = 66555166661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66555166661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2023189 + ... + 2055821.

It is an arithmetic number, because the mean of its divisors is an integer number (3584192220).

Almost surely, 2^66555166665 is an apocalyptic number.

66555166665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66555166665 is a deficient number, since it is larger than the sum of its proper divisors (48138984375).

66555166665 is a wasteful number, since it uses less digits than its factorization.

66555166665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43113.

The product of its digits is 29160000, while the sum is 57.

The spelling of 66555166665 in words is "sixty-six billion, five hundred fifty-five million, one hundred sixty-six thousand, six hundred sixty-five".