681424 has 10 divisors (see below), whose sum is σ = 1320290. Its totient is φ = 340704.

The previous prime is 681419. The next prime is 681427. The reversal of 681424 is 424186.

It can be written as a sum of positive squares in only one way, i.e., 462400 + 219024 = 680^2 + 468^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21279 + ... + 21310.

It is an arithmetic number, because the mean of its divisors is an integer number (132029).

681424 is a Friedman number, since it can be written as 8*(44^(2+1)-6), using all its digits and the basic arithmetic operations.

2⁶⁸¹⁴²⁴ is an apocalyptic number.

It is an amenable number.

681424 is a deficient number, since it is larger than the sum of its proper divisors (638866).

681424 is a wasteful number, since it uses less digits than its factorization.

681424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42597 (or 42591 counting only the distinct ones).

The product of its digits is 1536, while the sum is 25.

The square root of 681424 is about 825.4841003920. The cubic root of 681424 is about 87.9979338358.

The spelling of 681424 in words is "six hundred eighty-one thousand, four hundred twenty-four".