68591959921 has 4 divisors (see below), whose sum is σ = 71574219072. Its totient is φ = 65609700772.

The previous prime is 68591959867. The next prime is 68591959949. The reversal of 68591959921 is 12995919586.

It is the 106921-st star number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 68591959921 - 2²³ = 68583571313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68591959951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1491129541 + ... + 1491129586.

It is an arithmetic number, because the mean of its divisors is an integer number (17893554768).

Almost surely, 2^68591959921 is an apocalyptic number.

It is an amenable number.

68591959921 is a deficient number, since it is larger than the sum of its proper divisors (2982259151).

68591959921 is a wasteful number, since it uses less digits than its factorization.

68591959921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2982259150.

The product of its digits is 15746400, while the sum is 64.

The spelling of 68591959921 in words is "sixty-eight billion, five hundred ninety-one million, nine hundred fifty-nine thousand, nine hundred twenty-one".