688891349 has 2 divisors, whose sum is σ = 688891350. Its totient is φ = 688891348.

The previous prime is 688891339. The next prime is 688891429. The reversal of 688891349 is 943198886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 514836100 + 174055249 = 22690^2 + 13193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688891349 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 688891294 and 688891303.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688891319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344445674 + 344445675.

It is an arithmetic number, because the mean of its divisors is an integer number (344445675).

Almost surely, 2^688891349 is an apocalyptic number.

It is an amenable number.

688891349 is a deficient number, since it is larger than the sum of its proper divisors (1).

688891349 is an equidigital number, since it uses as much as digits as its factorization.

688891349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2985984, while the sum is 56.

The square root of 688891349 is about 26246.7397784944. The cubic root of 688891349 is about 883.1820701078.

The spelling of 688891349 in words is "six hundred eighty-eight million, eight hundred ninety-one thousand, three hundred forty-nine".