689383781 has 2 divisors, whose sum is σ = 689383782. Its totient is φ = 689383780.

The previous prime is 689383777. The next prime is 689383823. The reversal of 689383781 is 187383986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 414122500 + 275261281 = 20350^2 + 16591^2 .

It is a cyclic number.

It is not a de Polignac number, because 689383781 - 2² = 689383777 is a prime.

It is a super-2 number, since 2×689383781² = 950499995011711922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689383771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344691890 + 344691891.

It is an arithmetic number, because the mean of its divisors is an integer number (344691891).

Almost surely, 2^689383781 is an apocalyptic number.

It is an amenable number.

689383781 is a deficient number, since it is larger than the sum of its proper divisors (1).

689383781 is an equidigital number, since it uses as much as digits as its factorization.

689383781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 53.

The square root of 689383781 is about 26256.1189249287. The cubic root of 689383781 is about 883.3924581603.

The spelling of 689383781 in words is "six hundred eighty-nine million, three hundred eighty-three thousand, seven hundred eighty-one".