68721777 has 10 divisors (see below), whose sum is σ = 102658578. Its totient is φ = 45814464.

The previous prime is 68721773. The next prime is 68721787. The reversal of 68721777 is 77712786.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 67223601 + 1498176 = 8199^2 + 1224^2 .

It is not a de Polignac number, because 68721777 - 2² = 68721773 is a prime.

It is not an unprimeable number, because it can be changed into a prime (68721773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 424128 + ... + 424289.

Almost surely, 2^68721777 is an apocalyptic number.

It is an amenable number.

68721777 is a deficient number, since it is larger than the sum of its proper divisors (33936801).

68721777 is an equidigital number, since it uses as much as digits as its factorization.

68721777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848429 (or 848420 counting only the distinct ones).

The product of its digits is 230496, while the sum is 45.

The square root of 68721777 is about 8289.8598902515. The cubic root of 68721777 is about 409.6045701630.

It can be divided in two parts, 6872 and 1777, that added together give a square (8649 = 93²).

The spelling of 68721777 in words is "sixty-eight million, seven hundred twenty-one thousand, seven hundred seventy-seven".