77331720647 has 4 divisors (see below), whose sum is σ = 78391059360. Its totient is φ = 76272381936.

The previous prime is 77331720617. The next prime is 77331720649. The reversal of 77331720647 is 74602713377.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74602713377 = 64567 ⋅1155431.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77331720647 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 (77331720649) 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, 529669247 + ... + 529669392.

It is an arithmetic number, because the mean of its divisors is an integer number (19597764840).

Almost surely, 2^77331720647 is an apocalyptic number.

77331720647 is a deficient number, since it is larger than the sum of its proper divisors (1059338713).

77331720647 is a wasteful number, since it uses less digits than its factorization.

77331720647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059338712.

The product of its (nonzero) digits is 1037232, while the sum is 47.

The spelling of 77331720647 in words is "seventy-seven billion, three hundred thirty-one million, seven hundred twenty thousand, six hundred forty-seven".