681538 has 16 divisors (see below), whose sum is σ = 1201536. Its totient is φ = 285840.

The previous prime is 681523. The next prime is 681539. The reversal of 681538 is 835186.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (681539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 906 + ... + 1477.

It is an arithmetic number, because the mean of its divisors is an integer number (75096).

681538 is a Friedman number, since it can be written as 88^3+61+5, using all its digits and the basic arithmetic operations.

2⁶⁸¹⁵³⁸ is an apocalyptic number.

681538 is a deficient number, since it is larger than the sum of its proper divisors (519998).

681538 is a wasteful number, since it uses less digits than its factorization.

681538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2409.

The product of its digits is 5760, while the sum is 31.

The square root of 681538 is about 825.5531478954. The cubic root of 681538 is about 88.0028408174.

The spelling of 681538 in words is "six hundred eighty-one thousand, five hundred thirty-eight".