684727891 has 2 divisors, whose sum is σ = 684727892. Its totient is φ = 684727890.

The previous prime is 684727807. The next prime is 684727937. The reversal of 684727891 is 198727486.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 684727891 - 2¹⁷ = 684596819 is a prime.

It is not a weakly prime, because it can be changed into another prime (684727991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342363945 + 342363946.

It is an arithmetic number, because the mean of its divisors is an integer number (342363946).

Almost surely, 2^684727891 is an apocalyptic number.

684727891 is a deficient number, since it is larger than the sum of its proper divisors (1).

684727891 is an equidigital number, since it uses as much as digits as its factorization.

684727891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1354752, while the sum is 52.

The square root of 684727891 is about 26167.3057650191. The cubic root of 684727891 is about 881.3992421921.

The spelling of 684727891 in words is "six hundred eighty-four million, seven hundred twenty-seven thousand, eight hundred ninety-one".