68891993 has 4 divisors (see below), whose sum is σ = 68920320. Its totient is φ = 68863668.

The previous prime is 68891987. The next prime is 68892037. The reversal of 68891993 is 39919886.

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, and also an emirpimes, since its reverse is a distinct semiprime: 39919886 = 2 ⋅19959943.

It is a cyclic number.

It is not a de Polignac number, because 68891993 - 2⁸ = 68891737 is a prime.

It is a super-2 number, since 2×68891993² = 9492213399024098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68891903) 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, 10133 + ... + 15506.

It is an arithmetic number, because the mean of its divisors is an integer number (17230080).

Almost surely, 2^68891993 is an apocalyptic number.

It is an amenable number.

68891993 is a deficient number, since it is larger than the sum of its proper divisors (28327).

68891993 is a wasteful number, since it uses less digits than its factorization.

68891993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28326.

The product of its digits is 839808, while the sum is 53.

The square root of 68891993 is about 8300.1200593726. The cubic root of 68891993 is about 409.9424725949.

The spelling of 68891993 in words is "sixty-eight million, eight hundred ninety-one thousand, nine hundred ninety-three".