66809413 has 4 divisors (see below), whose sum is σ = 72883008. Its totient is φ = 60735820.

The previous prime is 66809399. The next prime is 66809443. The reversal of 66809413 is 31490866.

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 a de Polignac number, because none of the positive numbers 2^k-66809413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66809443) 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, 3036781 + ... + 3036802.

It is an arithmetic number, because the mean of its divisors is an integer number (18220752).

Almost surely, 2^66809413 is an apocalyptic number.

It is an amenable number.

66809413 is a deficient number, since it is larger than the sum of its proper divisors (6073595).

66809413 is a wasteful number, since it uses less digits than its factorization.

66809413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6073594.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 66809413 is about 8173.7025270070. The cubic root of 66809413 is about 405.7693307379.

The spelling of 66809413 in words is "sixty-six million, eight hundred nine thousand, four hundred thirteen".