66566656616655 has 16 divisors (see below), whose sum is σ = 114699469862880. Its totient is φ = 32771277103488.

The previous prime is 66566656616599. The next prime is 66566656616683. The reversal of 66566656616655 is 55661665666566.

It is not a de Polignac number, because 66566656616655 - 2⁸ = 66566656616399 is a prime.

It is a super-2 number, since 2×66566656616655² (a number of 28 digits) contains 22 as substring.

It is a congruent 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, 170683734720 + ... + 170683735109.

It is an arithmetic number, because the mean of its divisors is an integer number (7168716866430).

Almost surely, 2^{66566656616655} is an apocalyptic number.

66566656616655 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

66566656616655 is a deficient number, since it is larger than the sum of its proper divisors (48132813246225).

66566656616655 is a wasteful number, since it uses less digits than its factorization.

66566656616655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341367469850.

The product of its digits is 6298560000, while the sum is 75.

The spelling of 66566656616655 in words is "sixty-six trillion, five hundred sixty-six billion, six hundred fifty-six million, six hundred sixteen thousand, six hundred fifty-five".