681408 has 126 divisors (see below), whose sum is σ = 2417064. Its totient is φ = 179712.

The previous prime is 681407. The next prime is 681409. The reversal of 681408 is 804186.

It is an interprime number because it is at equal distance from previous prime (681407) and next prime (681409).

It is a tau number, because it is divible by the number of its divisors (126).

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681403) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 52410 + ... + 52422.

2⁶⁸¹⁴⁰⁸ 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 681408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1208532).

681408 is an abundant number, since it is smaller than the sum of its proper divisors (1735656).

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

681408 is a wasteful number, since it uses less digits than its factorization.

681408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51 (or 25 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 681408 is about 825.4744090522. The cubic root of 681408 is about 87.9972450928.

It can be divided in two parts, 681 and 408, that added together give a square (1089 = 33²).

The spelling of 681408 in words is "six hundred eighty-one thousand, four hundred eight".