77768321 has 4 divisors (see below), whose sum is σ = 77787732. Its totient is φ = 77748912.

The previous prime is 77768297. The next prime is 77768357. The reversal of 77768321 is 12386777.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12386777 = 13 ⋅952829.

It can be written as a sum of positive squares in 2 ways, for example, as 28206721 + 49561600 = 5311^2 + 7040^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77768321 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (77668321) 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, 1226 + ... + 12531.

It is an arithmetic number, because the mean of its divisors is an integer number (19446933).

Almost surely, 2^77768321 is an apocalyptic number.

It is an amenable number.

77768321 is a deficient number, since it is larger than the sum of its proper divisors (19411).

77768321 is a wasteful number, since it uses less digits than its factorization.

77768321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19410.

The product of its digits is 98784, while the sum is 41.

The square root of 77768321 is about 8818.6348716794. The cubic root of 77768321 is about 426.8424207433.

The spelling of 77768321 in words is "seventy-seven million, seven hundred sixty-eight thousand, three hundred twenty-one".