64639705687 has 8 divisors (see below), whose sum is σ = 68045391360. Its totient is φ = 61234379640.

The previous prime is 64639705661. The next prime is 64639705721. The reversal of 64639705687 is 78650793646.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64639705687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64639705657) 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 7 ways as a sum of consecutive naturals, for example, 329178 + ... + 487480.

It is an arithmetic number, because the mean of its divisors is an integer number (8505673920).

Almost surely, 2^64639705687 is an apocalyptic number.

64639705687 is a deficient number, since it is larger than the sum of its proper divisors (3405685673).

64639705687 is a wasteful number, since it uses less digits than its factorization.

64639705687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179813.

The product of its (nonzero) digits is 45722880, while the sum is 61.

The spelling of 64639705687 in words is "sixty-four billion, six hundred thirty-nine million, seven hundred five thousand, six hundred eighty-seven".