66860591539 has 4 divisors (see below), whose sum is σ = 76412104624. Its totient is φ = 57309078456.

The previous prime is 66860591533. The next prime is 66860591579. The reversal of 66860591539 is 93519506866.

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

It is not a de Polignac number, because 66860591539 - 2¹⁹ = 66860067251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66860591533) 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, 4775756532 + ... + 4775756545.

It is an arithmetic number, because the mean of its divisors is an integer number (19103026156).

Almost surely, 2^66860591539 is an apocalyptic number.

66860591539 is a deficient number, since it is larger than the sum of its proper divisors (9551513085).

66860591539 is an equidigital number, since it uses as much as digits as its factorization.

66860591539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9551513084.

The product of its (nonzero) digits is 10497600, while the sum is 58.

The spelling of 66860591539 in words is "sixty-six billion, eight hundred sixty million, five hundred ninety-one thousand, five hundred thirty-nine".