66744281 has 4 divisors (see below), whose sum is σ = 67875600. Its totient is φ = 65612964.

The previous prime is 66744259. The next prime is 66744289. The reversal of 66744281 is 18244766.

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: 18244766 = 2 ⋅9122383.

It is a cyclic number.

It is not a de Polignac number, because 66744281 - 2⁶ = 66744217 is a prime.

It is a super-2 number, since 2×66744281² = 8909598092413922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66744289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 565571 + ... + 565688.

It is an arithmetic number, because the mean of its divisors is an integer number (16968900).

Almost surely, 2^66744281 is an apocalyptic number.

It is an amenable number.

66744281 is a deficient number, since it is larger than the sum of its proper divisors (1131319).

66744281 is a wasteful number, since it uses less digits than its factorization.

66744281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1131318.

The product of its digits is 64512, while the sum is 38.

The square root of 66744281 is about 8169.7173145709. The cubic root of 66744281 is about 405.6374273636.

The spelling of 66744281 in words is "sixty-six million, seven hundred forty-four thousand, two hundred eighty-one".