66744481 has 4 divisors (see below), whose sum is σ = 67031172. Its totient is φ = 66457792.

The previous prime is 66744479. The next prime is 66744487. The reversal of 66744481 is 18444766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18444766 = 2 ⋅9222383.

It can be written as a sum of positive squares in 2 ways, for example, as 35283600 + 31460881 = 5940^2 + 5609^2 .

It is a cyclic number.

It is not a de Polignac number, because 66744481 - 2¹ = 66744479 is a prime.

It is a super-2 number, since 2×66744481² = 8909651487918722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) 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 not an unprimeable number, because it can be changed into a prime (66744487) 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, 142996 + ... + 143461.

It is an arithmetic number, because the mean of its divisors is an integer number (16757793).

Almost surely, 2^66744481 is an apocalyptic number.

It is an amenable number.

66744481 is a deficient number, since it is larger than the sum of its proper divisors (286691).

66744481 is a wasteful number, since it uses less digits than its factorization.

66744481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286690.

The product of its digits is 129024, while the sum is 40.

The square root of 66744481 is about 8169.7295548874. The cubic root of 66744481 is about 405.6378325289.

The spelling of 66744481 in words is "sixty-six million, seven hundred forty-four thousand, four hundred eighty-one".