688216393 has 2 divisors, whose sum is σ = 688216394. Its totient is φ = 688216392.

The previous prime is 688216387. The next prime is 688216409. The reversal of 688216393 is 393612886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 668119104 + 20097289 = 25848^2 + 4483^2 .

It is a cyclic number.

It is not a de Polignac number, because 688216393 - 2⁹ = 688215881 is a prime.

It is not a weakly prime, because it can be changed into another prime (688216493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344108196 + 344108197.

It is an arithmetic number, because the mean of its divisors is an integer number (344108197).

Almost surely, 2^688216393 is an apocalyptic number.

It is an amenable number.

688216393 is a deficient number, since it is larger than the sum of its proper divisors (1).

688216393 is an equidigital number, since it uses as much as digits as its factorization.

688216393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 46.

The square root of 688216393 is about 26233.8787258003. The cubic root of 688216393 is about 882.8935370284.

The spelling of 688216393 in words is "six hundred eighty-eight million, two hundred sixteen thousand, three hundred ninety-three".