687909769 has 2 divisors, whose sum is σ = 687909770. Its totient is φ = 687909768.

The previous prime is 687909713. The next prime is 687909793. The reversal of 687909769 is 967909786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404492544 + 283417225 = 20112^2 + 16835^2 .

It is a cyclic number.

It is not a de Polignac number, because 687909769 - 2¹⁷ = 687778697 is a prime.

It is a super-2 number, since 2×687909769² = 946439700571266722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (687909799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343954884 + 343954885.

It is an arithmetic number, because the mean of its divisors is an integer number (343954885).

Almost surely, 2^687909769 is an apocalyptic number.

It is an amenable number.

687909769 is a deficient number, since it is larger than the sum of its proper divisors (1).

687909769 is an equidigital number, since it uses as much as digits as its factorization.

687909769 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10287648, while the sum is 61.

The square root of 687909769 is about 26228.0340284971. The cubic root of 687909769 is about 882.7623977700.

The spelling of 687909769 in words is "six hundred eighty-seven million, nine hundred nine thousand, seven hundred sixty-nine".