66404405 has 4 divisors (see below), whose sum is σ = 79685292. Its totient is φ = 53123520.

The previous prime is 66404353. The next prime is 66404419. The reversal of 66404405 is 50440466.

66404405 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22221796 + 44182609 = 4714^2 + 6647^2 .

It is not a de Polignac number, because 66404405 - 2¹² = 66400309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6640436 + ... + 6640445.

It is an arithmetic number, because the mean of its divisors is an integer number (19921323).

Almost surely, 2^66404405 is an apocalyptic number.

It is an amenable number.

66404405 is a deficient number, since it is larger than the sum of its proper divisors (13280887).

66404405 is a wasteful number, since it uses less digits than its factorization.

66404405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13280886.

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

The square root of 66404405 is about 8148.8898016846. The cubic root of 66404405 is about 404.9477247979.

The spelling of 66404405 in words is "sixty-six million, four hundred four thousand, four hundred five".