689731387 has 2 divisors, whose sum is σ = 689731388. Its totient is φ = 689731386.

The previous prime is 689731381. The next prime is 689731409. The reversal of 689731387 is 783137986.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689731387 is a prime.

It is not a weakly prime, because it can be changed into another prime (689731381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344865693 + 344865694.

It is an arithmetic number, because the mean of its divisors is an integer number (344865694).

Almost surely, 2^689731387 is an apocalyptic number.

689731387 is a deficient number, since it is larger than the sum of its proper divisors (1).

689731387 is an equidigital number, since it uses as much as digits as its factorization.

689731387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 52.

The square root of 689731387 is about 26262.7376143463. The cubic root of 689731387 is about 883.5409100242.

The spelling of 689731387 in words is "six hundred eighty-nine million, seven hundred thirty-one thousand, three hundred eighty-seven".