684651769 has 2 divisors, whose sum is σ = 684651770. Its totient is φ = 684651768.

The previous prime is 684651767. The next prime is 684651791. The reversal of 684651769 is 967156486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 587432169 + 97219600 = 24237^2 + 9860^2 .

It is a cyclic number.

It is not a de Polignac number, because 684651769 - 2¹ = 684651767 is a prime.

It is a super-2 number, since 2×684651769² = 937496089589658722, which contains 22 as substring.

Together with 684651767, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (684651767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342325884 + 342325885.

It is an arithmetic number, because the mean of its divisors is an integer number (342325885).

Almost surely, 2^684651769 is an apocalyptic number.

It is an amenable number.

684651769 is a deficient number, since it is larger than the sum of its proper divisors (1).

684651769 is an equidigital number, since it uses as much as digits as its factorization.

684651769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 52.

The square root of 684651769 is about 26165.8511996075. The cubic root of 684651769 is about 881.3665789203.

The spelling of 684651769 in words is "six hundred eighty-four million, six hundred fifty-one thousand, seven hundred sixty-nine".