684979680 has 384 divisors, whose sum is σ = 2759049216. Its totient is φ = 138700800.

The previous prime is 684979649. The next prime is 684979699. The reversal of 684979680 is 86979486.

It is a self number, because there is not a number n which added to its sum of digits gives 684979680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1589065 + ... + 1589495.

It is an arithmetic number, because the mean of its divisors is an integer number (7185024).

Almost surely, 2^684979680 is an apocalyptic number.

684979680 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 684979680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1379524608).

684979680 is an abundant number, since it is smaller than the sum of its proper divisors (2074069536).

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

684979680 is a wasteful number, since it uses less digits than its factorization.

684979680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510 (or 502 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 57.

The square root of 684979680 is about 26172.1164600802. The cubic root of 684979680 is about 881.5072653644.

The spelling of 684979680 in words is "six hundred eighty-four million, nine hundred seventy-nine thousand, six hundred eighty".