66040409 has 4 divisors (see below), whose sum is σ = 69516240. Its totient is φ = 62564580.

The previous prime is 66040363. The next prime is 66040417. The reversal of 66040409 is 90404066.

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.

It is a cyclic number.

It is not a de Polignac number, because 66040409 - 2¹⁶ = 65974873 is a prime.

It is a super-2 number, since 2×66040409² = 8722671241774562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66040459) 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 3 ways as a sum of consecutive naturals, for example, 1737887 + ... + 1737924.

It is an arithmetic number, because the mean of its divisors is an integer number (17379060).

Almost surely, 2^66040409 is an apocalyptic number.

It is an amenable number.

66040409 is a deficient number, since it is larger than the sum of its proper divisors (3475831).

66040409 is a wasteful number, since it uses less digits than its factorization.

66040409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3475830.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 66040409 is about 8126.5250261105. The cubic root of 66040409 is about 404.2064612297.

The spelling of 66040409 in words is "sixty-six million, forty thousand, four hundred nine".