684421643 has 2 divisors, whose sum is σ = 684421644. Its totient is φ = 684421642.

The previous prime is 684421613. The next prime is 684421679. The reversal of 684421643 is 346124486.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 684421643 - 2²⁶ = 617312779 is a prime.

It is equal to p_35487182 and since 684421643 and 35487182 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 684421597 and 684421606.

It is not a weakly prime, because it can be changed into another prime (684421613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342210821 + 342210822.

It is an arithmetic number, because the mean of its divisors is an integer number (342210822).

Almost surely, 2^684421643 is an apocalyptic number.

684421643 is a deficient number, since it is larger than the sum of its proper divisors (1).

684421643 is an equidigital number, since it uses as much as digits as its factorization.

684421643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 38.

The square root of 684421643 is about 26161.4533808808. The cubic root of 684421643 is about 881.2678191793.

The spelling of 684421643 in words is "six hundred eighty-four million, four hundred twenty-one thousand, six hundred forty-three".