68108721 has 12 divisors (see below), whose sum is σ = 92081808. Its totient is φ = 44772984.

The previous prime is 68108707. The next prime is 68108723. The reversal of 68108721 is 12780186.

It is a happy number.

It is not a de Polignac number, because 68108721 - 2¹⁸ = 67846577 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (68108723) 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 11 ways as a sum of consecutive naturals, for example, 129966 + ... + 130488.

It is an arithmetic number, because the mean of its divisors is an integer number (7673484).

Almost surely, 2^68108721 is an apocalyptic number.

It is an amenable number.

68108721 is a deficient number, since it is larger than the sum of its proper divisors (23973087).

68108721 is an frugal number, since it uses more digits than its factorization.

68108721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 68108721 is about 8252.8007973051. The cubic root of 68108721 is about 408.3829245707.

The spelling of 68108721 in words is "sixty-eight million, one hundred eight thousand, seven hundred twenty-one".