66364561 has 4 divisors (see below), whose sum is σ = 66951972. Its totient is φ = 65777152.

The previous prime is 66364553. The next prime is 66364603. The reversal of 66364561 is 16546366.

66364561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8300161 + 58064400 = 2881^2 + 7620^2 .

It is a cyclic number.

It is not a de Polignac number, because 66364561 - 2³ = 66364553 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 66364561.

It is not an unprimeable number, because it can be changed into a prime (66364261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 293536 + ... + 293761.

It is an arithmetic number, because the mean of its divisors is an integer number (16737993).

Almost surely, 2^66364561 is an apocalyptic number.

It is an amenable number.

66364561 is a deficient number, since it is larger than the sum of its proper divisors (587411).

66364561 is a wasteful number, since it uses less digits than its factorization.

66364561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 587410.

The product of its digits is 77760, while the sum is 37.

The square root of 66364561 is about 8146.4446846462. Note that the first 3 decimals coincide. The cubic root of 66364561 is about 404.8667162901.

The spelling of 66364561 in words is "sixty-six million, three hundred sixty-four thousand, five hundred sixty-one".