684385780 has 36 divisors (see below), whose sum is σ = 1556276652.
Its totient is φ = 252695040.
The previous prime is 684385777. The next prime is 684385783. The reversal of 684385780 is 87583486.
It is an interprime number because it is at equal distance from previous prime (684385777) and next prime (684385783).
It can be written as a sum of positive squares in 6 ways, for example, as 240188004 + 444197776 = 15498^2 + 21076^2
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (684385783) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 97861 + ... + 104620.
It is an arithmetic number, because the mean of its divisors is an integer number (43229907).
Almost surely, 2684385780 is an apocalyptic number.
It is an amenable number.
684385780 is an abundant number, since it is smaller than the sum of its proper divisors (871890872).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
684385780 is a wasteful number, since it uses less digits than its factorization.
684385780 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 202516 (or 202501 counting only the distinct ones).
The product of its (nonzero) digits is 1290240, while the sum is 49.
The square root of 684385780 is about 26160.7679550888.
The cubic root of 684385780 is about 881.2524263971.
The spelling of 684385780 in words is "six hundred eighty-four million, three hundred eighty-five thousand, seven hundred eighty".