684729780 has 192 divisors, whose sum is σ = 2320109568. Its totient is φ = 147502080.

The previous prime is 684729779. The next prime is 684729781. The reversal of 684729780 is 87927486.

It is an interprime number because it is at equal distance from previous prime (684729779) and next prime (684729781).

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684729781) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 704695 + ... + 705665.

It is an arithmetic number, because the mean of its divisors is an integer number (12083904).

Almost surely, 2^684729780 is an apocalyptic number.

684729780 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684729780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1160054784).

684729780 is an abundant number, since it is smaller than the sum of its proper divisors (1635379788).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

684729780 is a wasteful number, since it uses less digits than its factorization.

684729780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086 (or 1084 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 51.

The square root of 684729780 is about 26167.3418596540. The cubic root of 684729780 is about 881.4000527144.

The spelling of 684729780 in words is "six hundred eighty-four million, seven hundred twenty-nine thousand, seven hundred eighty".