681021 has 16 divisors (see below), whose sum is σ = 1101120. Its totient is φ = 412560.

The previous prime is 681019. The next prime is 681041. The reversal of 681021 is 120186.

681021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 681021 - 2¹ = 681019 is a prime.

681021 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 680985 and 681003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 850 + ... + 1443.

It is an arithmetic number, because the mean of its divisors is an integer number (68820).

2⁶⁸¹⁰²¹ is an apocalyptic number.

It is an amenable number.

681021 is a deficient number, since it is larger than the sum of its proper divisors (420099).

681021 is a wasteful number, since it uses less digits than its factorization.

681021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2313 (or 2307 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 681021 is about 825.2399651011. The cubic root of 681021 is about 87.9805828371.

It can be divided in two parts, 68 and 1021, that added together give a square (1089 = 33²).

The spelling of 681021 in words is "six hundred eighty-one thousand, twenty-one".