68787979 has 4 divisors (see below), whose sum is σ = 74079376. Its totient is φ = 63496584.

The previous prime is 68787919. The next prime is 68787997. The reversal of 68787979 is 97978786.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 68787979 - 2¹³ = 68779787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68787919) 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 in 3 ways as a sum of consecutive naturals, for example, 2645679 + ... + 2645704.

It is an arithmetic number, because the mean of its divisors is an integer number (18519844).

Almost surely, 2^68787979 is an apocalyptic number.

68787979 is a deficient number, since it is larger than the sum of its proper divisors (5291397).

68787979 is a wasteful number, since it uses less digits than its factorization.

68787979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5291396.

The product of its digits is 10668672, while the sum is 61.

The square root of 68787979 is about 8293.8518795551. The cubic root of 68787979 is about 409.7360565716.

The spelling of 68787979 in words is "sixty-eight million, seven hundred eighty-seven thousand, nine hundred seventy-nine".