66561367 has 4 divisors (see below), whose sum is σ = 66637296. Its totient is φ = 66485440.

The previous prime is 66561359. The next prime is 66561373. The reversal of 66561367 is 76316566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76316566 = 2 ⋅38158283.

It is a cyclic number.

It is not a de Polignac number, because 66561367 - 2³ = 66561359 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66561337) 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, 36634 + ... + 38407.

It is an arithmetic number, because the mean of its divisors is an integer number (16659324).

Almost surely, 2^66561367 is an apocalyptic number.

66561367 is a deficient number, since it is larger than the sum of its proper divisors (75929).

66561367 is an equidigital number, since it uses as much as digits as its factorization.

66561367 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75928.

The product of its digits is 136080, while the sum is 40.

The square root of 66561367 is about 8158.5149996798. The cubic root of 66561367 is about 405.2665359260.

The spelling of 66561367 in words is "sixty-six million, five hundred sixty-one thousand, three hundred sixty-seven".