77970721065 has 8 divisors (see below), whose sum is σ = 124753153728. Its totient is φ = 41584384560.

The previous prime is 77970721043. The next prime is 77970721067. The reversal of 77970721065 is 56012707977.

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

It is not a de Polignac number, because 77970721065 - 2¹³ = 77970712873 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 77970720999 and 77970721017.

It is not an unprimeable number, because it can be changed into a prime (77970721067) 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, 2599024021 + ... + 2599024050.

It is an arithmetic number, because the mean of its divisors is an integer number (15594144216).

Almost surely, 2^77970721065 is an apocalyptic number.

It is an amenable number.

77970721065 is a deficient number, since it is larger than the sum of its proper divisors (46782432663).

77970721065 is a wasteful number, since it uses less digits than its factorization.

77970721065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5198048079.

The product of its (nonzero) digits is 1296540, while the sum is 51.

The spelling of 77970721065 in words is "seventy-seven billion, nine hundred seventy million, seven hundred twenty-one thousand, sixty-five".