68218139 has 4 divisors (see below), whose sum is σ = 74419800. Its totient is φ = 62016480.

The previous prime is 68218123. The next prime is 68218169. The reversal of 68218139 is 93181286.

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 68218139 - 2⁴ = 68218123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68218169) 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, 3100814 + ... + 3100835.

It is an arithmetic number, because the mean of its divisors is an integer number (18604950).

Almost surely, 2^68218139 is an apocalyptic number.

68218139 is a deficient number, since it is larger than the sum of its proper divisors (6201661).

68218139 is a wasteful number, since it uses less digits than its factorization.

68218139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6201660.

The product of its digits is 20736, while the sum is 38.

The square root of 68218139 is about 8259.4272803869. The cubic root of 68218139 is about 408.6014992981.

The spelling of 68218139 in words is "sixty-eight million, two hundred eighteen thousand, one hundred thirty-nine".