166556551565 has 8 divisors (see below), whose sum is σ = 200331595008. Its totient is φ = 132936085840.

The previous prime is 166556551559. The next prime is 166556551571. The reversal of 166556551565 is 565155655661.

166556551565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (166556551559) and next prime (166556551571).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 166556551565 - 2⁴ = 166556551549 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166556551565.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38642057 + ... + 38646366.

It is an arithmetic number, because the mean of its divisors is an integer number (25041449376).

Almost surely, 2^166556551565 is an apocalyptic number.

It is an amenable number.

166556551565 is a deficient number, since it is larger than the sum of its proper divisors (33775043443).

166556551565 is an equidigital number, since it uses as much as digits as its factorization.

166556551565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77288859.

The product of its digits is 20250000, while the sum is 56.

The spelling of 166556551565 in words is "one hundred sixty-six billion, five hundred fifty-six million, five hundred fifty-one thousand, five hundred sixty-five".