66706247 has 4 divisors (see below), whose sum is σ = 66919680. Its totient is φ = 66492816.

The previous prime is 66706243. The next prime is 66706253. The reversal of 66706247 is 74260766.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74260766 = 2 ⋅37130383.

It is a cyclic number.

It is not a de Polignac number, because 66706247 - 2² = 66706243 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 66706247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66706243) 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, 106247 + ... + 106872.

It is an arithmetic number, because the mean of its divisors is an integer number (16729920).

Almost surely, 2^66706247 is an apocalyptic number.

66706247 is a deficient number, since it is larger than the sum of its proper divisors (213433).

66706247 is a wasteful number, since it uses less digits than its factorization.

66706247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213432.

The product of its (nonzero) digits is 84672, while the sum is 38.

The square root of 66706247 is about 8167.3892401428. The cubic root of 66706247 is about 405.5603623569.

The spelling of 66706247 in words is "sixty-six million, seven hundred six thousand, two hundred forty-seven".