688421387 has 2 divisors, whose sum is σ = 688421388. Its totient is φ = 688421386.

The previous prime is 688421369. The next prime is 688421389. The reversal of 688421387 is 783124886.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 688421387 - 2⁶ = 688421323 is a prime.

Together with 688421389, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (688421389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344210693 + 344210694.

It is an arithmetic number, because the mean of its divisors is an integer number (344210694).

Almost surely, 2^688421387 is an apocalyptic number.

688421387 is a deficient number, since it is larger than the sum of its proper divisors (1).

688421387 is an equidigital number, since it uses as much as digits as its factorization.

688421387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 516096, while the sum is 47.

The square root of 688421387 is about 26237.7854820105. The cubic root of 688421387 is about 882.9811886802.

The spelling of 688421387 in words is "six hundred eighty-eight million, four hundred twenty-one thousand, three hundred eighty-seven".