166115555 has 4 divisors (see below), whose sum is σ = 199338672. Its totient is φ = 132892440.

The previous prime is 166115549. The next prime is 166115557. The reversal of 166115555 is 555511661.

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

It is not a de Polignac number, because 166115555 - 2²⁴ = 149338339 is a prime.

It is a super-2 number, since 2×166115555² = 55188755225916050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166115557) 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, 16611551 + ... + 16611560.

It is an arithmetic number, because the mean of its divisors is an integer number (49834668).

Almost surely, 2^166115555 is an apocalyptic number.

166115555 is a deficient number, since it is larger than the sum of its proper divisors (33223117).

166115555 is an equidigital number, since it uses as much as digits as its factorization.

166115555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33223116.

The product of its digits is 22500, while the sum is 35.

The square root of 166115555 is about 12888.5823502820. The cubic root of 166115555 is about 549.7139614585.

The spelling of 166115555 in words is "one hundred sixty-six million, one hundred fifteen thousand, five hundred fifty-five".