681333491 has 4 divisors (see below), whose sum is σ = 681850584. Its totient is φ = 680816400.

The previous prime is 681333473. The next prime is 681333493. The reversal of 681333491 is 194333186.

It is a happy number.

681333491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 681333491 - 2⁶ = 681333427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681333493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256565 + ... + 259206.

It is an arithmetic number, because the mean of its divisors is an integer number (170462646).

Almost surely, 2^681333491 is an apocalyptic number.

681333491 is a deficient number, since it is larger than the sum of its proper divisors (517093).

681333491 is a wasteful number, since it uses less digits than its factorization.

681333491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517092.

The product of its digits is 46656, while the sum is 38.

The square root of 681333491 is about 26102.3656207632. The cubic root of 681333491 is about 879.9403760395.

It can be divided in two parts, 6813 and 33491, that added together give a palindrome (40304).

The spelling of 681333491 in words is "six hundred eighty-one million, three hundred thirty-three thousand, four hundred ninety-one".