664538687 has 8 divisors (see below), whose sum is σ = 718600896. Its totient is φ = 612140032.

The previous prime is 664538681. The next prime is 664538689. The reversal of 664538687 is 786835466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 664538687 - 2⁸ = 664538431 is a prime.

It is a super-2 number, since 2×664538687² = 883223333039367938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664538681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 415058 + ... + 416655.

It is an arithmetic number, because the mean of its divisors is an integer number (89825112).

Almost surely, 2^664538687 is an apocalyptic number.

664538687 is a deficient number, since it is larger than the sum of its proper divisors (54062209).

664538687 is a wasteful number, since it uses less digits than its factorization.

664538687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831777.

The product of its digits is 5806080, while the sum is 53.

The square root of 664538687 is about 25778.6478892901. The cubic root of 664538687 is about 872.6499932877.

The spelling of 664538687 in words is "six hundred sixty-four million, five hundred thirty-eight thousand, six hundred eighty-seven".