155720166121171 has 4 divisors (see below), whose sum is σ = 155729070030600. Its totient is φ = 155711262211744.

The previous prime is 155720166121153. The next prime is 155720166121181. The reversal of 155720166121171 is 171121661027551.

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 155720166121171 - 2¹⁷ = 155720165990099 is a prime.

It is a super-2 number, since 2×155720166121171² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155720166121111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4451928481 + ... + 4451963458.

It is an arithmetic number, because the mean of its divisors is an integer number (38932267507650).

Almost surely, 2^{155720166121171} is an apocalyptic number.

155720166121171 is a deficient number, since it is larger than the sum of its proper divisors (8903909429).

155720166121171 is an equidigital number, since it uses as much as digits as its factorization.

155720166121171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8903909428.

The product of its (nonzero) digits is 176400, while the sum is 46.

The spelling of 155720166121171 in words is "one hundred fifty-five trillion, seven hundred twenty billion, one hundred sixty-six million, one hundred twenty-one thousand, one hundred seventy-one".