68121491 has 4 divisors (see below), whose sum is σ = 68145192. Its totient is φ = 68097792.

The previous prime is 68121467. The next prime is 68121497. The reversal of 68121491 is 19412186.

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 68121491 - 2¹⁰ = 68120467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68121497) 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, 6830 + ... + 13523.

It is an arithmetic number, because the mean of its divisors is an integer number (17036298).

Almost surely, 2^68121491 is an apocalyptic number.

68121491 is a deficient number, since it is larger than the sum of its proper divisors (23701).

68121491 is a wasteful number, since it uses less digits than its factorization.

68121491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23700.

The product of its digits is 3456, while the sum is 32.

The square root of 68121491 is about 8253.5744377815. The cubic root of 68121491 is about 408.4084461387.

The spelling of 68121491 in words is "sixty-eight million, one hundred twenty-one thousand, four hundred ninety-one".