681551 has 8 divisors (see below), whose sum is σ = 742560. Its totient is φ = 621792.

The previous prime is 681539. The next prime is 681557. The reversal of 681551 is 155186.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 681551 - 2⁶ = 681487 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 681551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681557) 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 7 ways as a sum of consecutive naturals, for example, 1085 + ... + 1593.

It is an arithmetic number, because the mean of its divisors is an integer number (92820).

2⁶⁸¹⁵⁵¹ is an apocalyptic number.

681551 is a deficient number, since it is larger than the sum of its proper divisors (61009).

681551 is a wasteful number, since it uses less digits than its factorization.

681551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625.

The product of its digits is 1200, while the sum is 26.

The square root of 681551 is about 825.5610213667. The cubic root of 681551 is about 88.0034003507.

The spelling of 681551 in words is "six hundred eighty-one thousand, five hundred fifty-one".