681533 has 4 divisors (see below), whose sum is σ = 690240. Its totient is φ = 672828.

The previous prime is 681523. The next prime is 681539. The reversal of 681533 is 335186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 335186 = 2 ⋅167593.

It is a cyclic number.

It is not a de Polignac number, because 681533 - 2¹⁰ = 680509 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681539) 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 3 ways as a sum of consecutive naturals, for example, 4235 + ... + 4392.

It is an arithmetic number, because the mean of its divisors is an integer number (172560).

681533 is a Friedman number, since it can be written as 61+(83+5)^3, using all its digits and the basic arithmetic operations.

2⁶⁸¹⁵³³ is an apocalyptic number.

It is an amenable number.

681533 is a deficient number, since it is larger than the sum of its proper divisors (8707).

681533 is an equidigital number, since it uses as much as digits as its factorization.

681533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8706.

The product of its digits is 2160, while the sum is 26.

The square root of 681533 is about 825.5501196172. The cubic root of 681533 is about 88.0026256104.

The spelling of 681533 in words is "six hundred eighty-one thousand, five hundred thirty-three".