688216387 has 2 divisors, whose sum is σ = 688216388. Its totient is φ = 688216386.

The previous prime is 688216367. The next prime is 688216393. The reversal of 688216387 is 783612886.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 688216387 - 2⁷ = 688216259 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 688216387.

It is not a weakly prime, because it can be changed into another prime (688216307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344108193 + 344108194.

It is an arithmetic number, because the mean of its divisors is an integer number (344108194).

Almost surely, 2^688216387 is an apocalyptic number.

688216387 is a deficient number, since it is larger than the sum of its proper divisors (1).

688216387 is an equidigital number, since it uses as much as digits as its factorization.

688216387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 774144, while the sum is 49.

The square root of 688216387 is about 26233.8786114444. The cubic root of 688216387 is about 882.8935344627.

The spelling of 688216387 in words is "six hundred eighty-eight million, two hundred sixteen thousand, three hundred eighty-seven".