684385777 has 2 divisors, whose sum is σ = 684385778. Its totient is φ = 684385776.

The previous prime is 684385763. The next prime is 684385783. The reversal of 684385777 is 777583486.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 498227041 + 186158736 = 22321^2 + 13644^2 .

It is a cyclic number.

It is not a de Polignac number, because 684385777 - 2¹⁵ = 684353009 is a prime.

It is not a weakly prime, because it can be changed into another prime (684385277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342192888 + 342192889.

It is an arithmetic number, because the mean of its divisors is an integer number (342192889).

Almost surely, 2^684385777 is an apocalyptic number.

It is an amenable number.

684385777 is a deficient number, since it is larger than the sum of its proper divisors (1).

684385777 is an equidigital number, since it uses as much as digits as its factorization.

684385777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7902720, while the sum is 55.

The square root of 684385777 is about 26160.7678977510. The cubic root of 684385777 is about 881.2524251094.

The spelling of 684385777 in words is "six hundred eighty-four million, three hundred eighty-five thousand, seven hundred seventy-seven".