664821006587 has 4 divisors (see below), whose sum is σ = 665487829056. Its totient is φ = 664154184120.

The previous prime is 664821006583. The next prime is 664821006607. The reversal of 664821006587 is 785600128466.

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: 785600128466 = 2 ⋅392800064233.

It is a cyclic number.

It is not a de Polignac number, because 664821006587 - 2² = 664821006583 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664821006583) 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, 333409739 + ... + 333411732.

It is an arithmetic number, because the mean of its divisors is an integer number (166371957264).

Almost surely, 2^664821006587 is an apocalyptic number.

664821006587 is a deficient number, since it is larger than the sum of its proper divisors (666822469).

664821006587 is an equidigital number, since it uses as much as digits as its factorization.

664821006587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666822468.

The product of its (nonzero) digits is 3870720, while the sum is 53.

The spelling of 664821006587 in words is "six hundred sixty-four billion, eight hundred twenty-one million, six thousand, five hundred eighty-seven".