77964720109 has 4 divisors (see below), whose sum is σ = 78014924316. Its totient is φ = 77914515904.

The previous prime is 77964720083. The next prime is 77964720121. The reversal of 77964720109 is 90102746977.

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 4355604009 + 73609116100 = 65997^2 + 271310^2 .

It is a cyclic number.

It is not a de Polignac number, because 77964720109 - 2⁵ = 77964720077 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 (77964720149) 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, 25099774 + ... + 25102879.

It is an arithmetic number, because the mean of its divisors is an integer number (19503731079).

Almost surely, 2^77964720109 is an apocalyptic number.

It is an amenable number.

77964720109 is a deficient number, since it is larger than the sum of its proper divisors (50204207).

77964720109 is a wasteful number, since it uses less digits than its factorization.

77964720109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50204206.

The product of its (nonzero) digits is 1333584, while the sum is 52.

The spelling of 77964720109 in words is "seventy-seven billion, nine hundred sixty-four million, seven hundred twenty thousand, one hundred nine".