688081193 has 4 divisors (see below), whose sum is σ = 706678020. Its totient is φ = 669484368.

The previous prime is 688081189. The next prime is 688081201. The reversal of 688081193 is 391180886.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 536987929 + 151093264 = 23173^2 + 12292^2 .

It is a cyclic number.

It is not a de Polignac number, because 688081193 - 2² = 688081189 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688081153) 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 3 ways as a sum of consecutive naturals, for example, 9298358 + ... + 9298431.

It is an arithmetic number, because the mean of its divisors is an integer number (176669505).

Almost surely, 2^688081193 is an apocalyptic number.

It is an amenable number.

688081193 is a deficient number, since it is larger than the sum of its proper divisors (18596827).

688081193 is a wasteful number, since it uses less digits than its factorization.

688081193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18596826.

The product of its (nonzero) digits is 82944, while the sum is 44.

The square root of 688081193 is about 26231.3017786003. The cubic root of 688081193 is about 882.8357184775.

The spelling of 688081193 in words is "six hundred eighty-eight million, eighty-one thousand, one hundred ninety-three".