166197578 has 4 divisors (see below), whose sum is σ = 249296370. Its totient is φ = 83098788.

The previous prime is 166197557. The next prime is 166197583. The reversal of 166197578 is 875791661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 875791661 = 6841 ⋅128021.

It can be written as a sum of positive squares in only one way, i.e., 162129289 + 4068289 = 12733^2 + 2017^2 .

It is a Curzon 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 as a sum of consecutive naturals, namely, 41549393 + ... + 41549396.

Almost surely, 2^166197578 is an apocalyptic number.

166197578 is a deficient number, since it is larger than the sum of its proper divisors (83098792).

166197578 is an equidigital number, since it uses as much as digits as its factorization.

166197578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83098791.

The product of its digits is 635040, while the sum is 50.

The square root of 166197578 is about 12891.7639599862. The cubic root of 166197578 is about 549.8044241268.

The spelling of 166197578 in words is "one hundred sixty-six million, one hundred ninety-seven thousand, five hundred seventy-eight".