684692640 has 144 divisors (see below), whose sum is σ = 2376410400. Its totient is φ = 179467776.

The previous prime is 684692627. The next prime is 684692641. The reversal of 684692640 is 46296486.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×684692640² = 937608022540339200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (684692641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80931 + ... + 88989.

It is an arithmetic number, because the mean of its divisors is an integer number (16502850).

Almost surely, 2^684692640 is an apocalyptic number.

684692640 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 684692640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1188205200).

684692640 is an abundant number, since it is smaller than the sum of its proper divisors (1691717760).

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

684692640 is a wasteful number, since it uses less digits than its factorization.

684692640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8139 (or 8128 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The square root of 684692640 is about 26166.6321868138. The cubic root of 684692640 is about 881.3841166031.

The spelling of 684692640 in words is "six hundred eighty-four million, six hundred ninety-two thousand, six hundred forty".