66820539 has 4 divisors (see below), whose sum is σ = 89094056. Its totient is φ = 44547024.

The previous prime is 66820513. The next prime is 66820547. The reversal of 66820539 is 93502866.

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

It is not a de Polignac number, because 66820539 - 2⁹ = 66820027 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66820497 and 66820506.

It is not an unprimeable number, because it can be changed into a prime (66827539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11136754 + ... + 11136759.

It is an arithmetic number, because the mean of its divisors is an integer number (22273514).

Almost surely, 2^66820539 is an apocalyptic number.

66820539 is a deficient number, since it is larger than the sum of its proper divisors (22273517).

66820539 is a wasteful number, since it uses less digits than its factorization.

66820539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22273516.

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 66820539 is about 8174.3830959896. The cubic root of 66820539 is about 405.7918542057.

The spelling of 66820539 in words is "sixty-six million, eight hundred twenty thousand, five hundred thirty-nine".