66258809 has 8 divisors (see below), whose sum is σ = 70946280. Its totient is φ = 61659136.

The previous prime is 66258781. The next prime is 66258839. The reversal of 66258809 is 90885266.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 24720784 + 41538025 = 4972^2 + 6445^2 .

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

It is not a de Polignac number, because 66258809 - 2¹⁶ = 66193273 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66258809.

It is not an unprimeable number, because it can be changed into a prime (66258839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20384 + ... + 23409.

It is an arithmetic number, because the mean of its divisors is an integer number (8868285).

Almost surely, 2^66258809 is an apocalyptic number.

It is an amenable number.

66258809 is a deficient number, since it is larger than the sum of its proper divisors (4687471).

66258809 is a wasteful number, since it uses less digits than its factorization.

66258809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43899.

The product of its (nonzero) digits is 207360, while the sum is 44.

The square root of 66258809 is about 8139.9514126314. The cubic root of 66258809 is about 404.6515501098.

The spelling of 66258809 in words is "sixty-six million, two hundred fifty-eight thousand, eight hundred nine".