684805399 has 2 divisors, whose sum is σ = 684805400. Its totient is φ = 684805398.

The previous prime is 684805393. The next prime is 684805409. The reversal of 684805399 is 993508486.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 684805399 - 2²⁵ = 651250967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684805393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342402699 + 342402700.

It is an arithmetic number, because the mean of its divisors is an integer number (342402700).

Almost surely, 2^684805399 is an apocalyptic number.

684805399 is a deficient number, since it is larger than the sum of its proper divisors (1).

684805399 is an equidigital number, since it uses as much as digits as its factorization.

684805399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1866240, while the sum is 52.

The square root of 684805399 is about 26168.7867315243. The cubic root of 684805399 is about 881.4324976969.

The spelling of 684805399 in words is "six hundred eighty-four million, eight hundred five thousand, three hundred ninety-nine".