66144181 has 4 divisors (see below), whose sum is σ = 67551552. Its totient is φ = 64736812.

The previous prime is 66144167. The next prime is 66144223. The reversal of 66144181 is 18144166.

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: 18144166 = 2 ⋅9072083.

It is a cyclic number.

It is not a de Polignac number, because 66144181 - 2⁹ = 66143669 is a prime.

It is a super-2 number, since 2×66144181² = 8750105360321522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66144101) 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, 703615 + ... + 703708.

It is an arithmetic number, because the mean of its divisors is an integer number (16887888).

Almost surely, 2^66144181 is an apocalyptic number.

It is an amenable number.

66144181 is a deficient number, since it is larger than the sum of its proper divisors (1407371).

66144181 is a wasteful number, since it uses less digits than its factorization.

66144181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1407370.

The product of its digits is 4608, while the sum is 31.

The square root of 66144181 is about 8132.9072907540. The cubic root of 66144181 is about 404.4180658243.

The spelling of 66144181 in words is "sixty-six million, one hundred forty-four thousand, one hundred eighty-one".