66806247 has 8 divisors (see below), whose sum is σ = 89136256. Its totient is φ = 44506872.

The previous prime is 66806213. The next prime is 66806251. The reversal of 66806247 is 74260866.

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

It is not a de Polignac number, because 66806247 - 2⁶ = 66806183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66806347) 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, 1963 + ... + 11724.

It is an arithmetic number, because the mean of its divisors is an integer number (11142032).

Almost surely, 2^66806247 is an apocalyptic number.

66806247 is a deficient number, since it is larger than the sum of its proper divisors (22330009).

66806247 is a wasteful number, since it uses less digits than its factorization.

66806247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15317.

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 66806247 is about 8173.5088548310. The cubic root of 66806247 is about 405.7629210324.

The spelling of 66806247 in words is "sixty-six million, eight hundred six thousand, two hundred forty-seven".