166501561655 has 32 divisors (see below), whose sum is σ = 234768941568. Its totient is φ = 111759811200.

The previous prime is 166501561649. The next prime is 166501561661. The reversal of 166501561655 is 556165105661.

It is an interprime number because it is at equal distance from previous prime (166501561649) and next prime (166501561661).

It is not a de Polignac number, because 166501561655 - 2⁶ = 166501561591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5914022 + ... + 5942108.

It is an arithmetic number, because the mean of its divisors is an integer number (7336529424).

Almost surely, 2^166501561655 is an apocalyptic number.

166501561655 is a deficient number, since it is larger than the sum of its proper divisors (68267379913).

166501561655 is a wasteful number, since it uses less digits than its factorization.

166501561655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36407.

The product of its (nonzero) digits is 810000, while the sum is 47.

The spelling of 166501561655 in words is "one hundred sixty-six billion, five hundred one million, five hundred sixty-one thousand, six hundred fifty-five".