684851420 has 48 divisors (see below), whose sum is σ = 1572697728. Its totient is φ = 248439360.

The previous prime is 684851399. The next prime is 684851423. The reversal of 684851420 is 24158486.

It is a happy number.

It is a Smith number, since the sum of its digits (38) 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 (684851423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93947 + ... + 100973.

It is an arithmetic number, because the mean of its divisors is an integer number (32764536).

Almost surely, 2^684851420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684851420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786348864).

684851420 is an abundant number, since it is smaller than the sum of its proper divisors (887846308).

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

684851420 is a wasteful number, since it uses less digits than its factorization.

684851420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7490 (or 7488 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 38.

The square root of 684851420 is about 26169.6660276741. Note that the first 3 decimals coincide. The cubic root of 684851420 is about 881.4522422337.

The spelling of 684851420 in words is "six hundred eighty-four million, eight hundred fifty-one thousand, four hundred twenty".