66278447 has 4 divisors (see below), whose sum is σ = 66479016. Its totient is φ = 66077880.

The previous prime is 66278423. The next prime is 66278453. The reversal of 66278447 is 74487266.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66278447 - 2¹⁶ = 66212911 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66278398 and 66278407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66274447) 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, 99788 + ... + 100449.

It is an arithmetic number, because the mean of its divisors is an integer number (16619754).

Almost surely, 2^66278447 is an apocalyptic number.

66278447 is a deficient number, since it is larger than the sum of its proper divisors (200569).

66278447 is a wasteful number, since it uses less digits than its factorization.

66278447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200568.

The product of its digits is 451584, while the sum is 44.

The square root of 66278447 is about 8141.1575958214. The cubic root of 66278447 is about 404.6915234724.

The spelling of 66278447 in words is "sixty-six million, two hundred seventy-eight thousand, four hundred forty-seven".