68721979 has 2 divisors, whose sum is σ = 68721980. Its totient is φ = 68721978.

The previous prime is 68721977. The next prime is 68722013. The reversal of 68721979 is 97912786.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68721979 - 2¹ = 68721977 is a prime.

Together with 68721977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (68721971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34360989 + 34360990.

It is an arithmetic number, because the mean of its divisors is an integer number (34360990).

Almost surely, 2^68721979 is an apocalyptic number.

68721979 is a deficient number, since it is larger than the sum of its proper divisors (1).

68721979 is an equidigital number, since it uses as much as digits as its factorization.

68721979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024, while the sum is 49.

The square root of 68721979 is about 8289.8720738019. The cubic root of 68721979 is about 409.6049714916.

The spelling of 68721979 in words is "sixty-eight million, seven hundred twenty-one thousand, nine hundred seventy-nine".