66880409 has 4 divisors (see below), whose sum is σ = 69186660. Its totient is φ = 64574160.

The previous prime is 66880391. The next prime is 66880417. The reversal of 66880409 is 90408866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90408866 = 2 ⋅45204433.

It can be written as a sum of positive squares in 2 ways, for example, as 14462809 + 52417600 = 3803^2 + 7240^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66880409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66880469) 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, 1153082 + ... + 1153139.

It is an arithmetic number, because the mean of its divisors is an integer number (17296665).

Almost surely, 2^66880409 is an apocalyptic number.

It is an amenable number.

66880409 is a deficient number, since it is larger than the sum of its proper divisors (2306251).

66880409 is a wasteful number, since it uses less digits than its factorization.

66880409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2306250.

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 66880409 is about 8178.0443261210. The cubic root of 66880409 is about 405.9130120932.

The spelling of 66880409 in words is "sixty-six million, eight hundred eighty thousand, four hundred nine".