181666057 has 4 divisors (see below), whose sum is σ = 182466576. Its totient is φ = 180865540.

The previous prime is 181666031. The next prime is 181666081. The reversal of 181666057 is 750666181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 750666181 = 757 ⋅991633.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181666057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181666027) 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, 399919 + ... + 400372.

It is an arithmetic number, because the mean of its divisors is an integer number (45616644).

Almost surely, 2^181666057 is an apocalyptic number.

It is an amenable number.

181666057 is a deficient number, since it is larger than the sum of its proper divisors (800519).

181666057 is an equidigital number, since it uses as much as digits as its factorization.

181666057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800518.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 181666057 is about 13478.3551296143. The cubic root of 181666057 is about 566.3582920005.

The spelling of 181666057 in words is "one hundred eighty-one million, six hundred sixty-six thousand, fifty-seven".