68778191 has 4 divisors (see below), whose sum is σ = 69720432. Its totient is φ = 67835952.

The previous prime is 68778163. The next prime is 68778217. The reversal of 68778191 is 19187786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19187786 = 2 ⋅9593893.

It is a cyclic number.

It is not a de Polignac number, because 68778191 - 2²² = 64583887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68778121) 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, 471011 + ... + 471156.

It is an arithmetic number, because the mean of its divisors is an integer number (17430108).

Almost surely, 2^68778191 is an apocalyptic number.

68778191 is a deficient number, since it is larger than the sum of its proper divisors (942241).

68778191 is an equidigital number, since it uses as much as digits as its factorization.

68778191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 942240.

The product of its digits is 169344, while the sum is 47.

The square root of 68778191 is about 8293.2617829175. The cubic root of 68778191 is about 409.7166215539.

The spelling of 68778191 in words is "sixty-eight million, seven hundred seventy-eight thousand, one hundred ninety-one".