66440405 has 8 divisors (see below), whose sum is σ = 80460600. Its totient is φ = 52664256.

The previous prime is 66440401. The next prime is 66440447. The reversal of 66440405 is 50404466.

It can be written as a sum of positive squares in 4 ways, for example, as 10982596 + 55457809 = 3314^2 + 7447^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66440405 - 2² = 66440401 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66440401) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 60410 + ... + 61499.

It is an arithmetic number, because the mean of its divisors is an integer number (10057575).

Almost surely, 2^66440405 is an apocalyptic number.

It is an amenable number.

66440405 is a deficient number, since it is larger than the sum of its proper divisors (14020195).

66440405 is a wasteful number, since it uses less digits than its factorization.

66440405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122023.

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 66440405 is about 8151.0983922414. The cubic root of 66440405 is about 405.0208900468.

The spelling of 66440405 in words is "sixty-six million, four hundred forty thousand, four hundred five".