166000011565551 has 4 divisors (see below), whose sum is σ = 221333348754072. Its totient is φ = 110666674377032.

The previous prime is 166000011565547. The next prime is 166000011565559. The reversal of 166000011565551 is 155565110000661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 166000011565551 - 2² = 166000011565547 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166000011565559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27666668594256 + ... + 27666668594261.

It is an arithmetic number, because the mean of its divisors is an integer number (55333337188518).

Almost surely, 2^{166000011565551} is an apocalyptic number.

166000011565551 is a deficient number, since it is larger than the sum of its proper divisors (55333337188521).

166000011565551 is an equidigital number, since it uses as much as digits as its factorization.

166000011565551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55333337188520.

The product of its (nonzero) digits is 135000, while the sum is 42.

The spelling of 166000011565551 in words is "one hundred sixty-six trillion, eleven million, five hundred sixty-five thousand, five hundred fifty-one".