656719538689 has 4 divisors (see below), whose sum is σ = 656761295956. Its totient is φ = 656677781424.

The previous prime is 656719538681. The next prime is 656719538707. The reversal of 656719538689 is 986835917656.

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

It can be written as a sum of positive squares in 2 ways, for example, as 218486130625 + 438233408064 = 467425^2 + 661992^2 .

It is a cyclic number.

It is not a de Polignac number, because 656719538689 - 2³ = 656719538681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656719538681) 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 3 ways as a sum of consecutive naturals, for example, 20855034 + ... + 20886499.

It is an arithmetic number, because the mean of its divisors is an integer number (164190323989).

Almost surely, 2^656719538689 is an apocalyptic number.

It is an amenable number.

656719538689 is a deficient number, since it is larger than the sum of its proper divisors (41757267).

656719538689 is a wasteful number, since it uses less digits than its factorization.

656719538689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41757266.

The product of its digits is 587865600, while the sum is 73.

The spelling of 656719538689 in words is "six hundred fifty-six billion, seven hundred nineteen million, five hundred thirty-eight thousand, six hundred eighty-nine".