688530581 has 4 divisors (see below), whose sum is σ = 691148832. Its totient is φ = 685912332.

The previous prime is 688530571. The next prime is 688530587. The reversal of 688530581 is 185035886.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688530581 is a prime.

It is a super-2 number, since 2×688530581² = 948148721944395122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688530587) 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, 1308731 + ... + 1309256.

It is an arithmetic number, because the mean of its divisors is an integer number (172787208).

Almost surely, 2^688530581 is an apocalyptic number.

It is an amenable number.

688530581 is a deficient number, since it is larger than the sum of its proper divisors (2618251).

688530581 is a wasteful number, since it uses less digits than its factorization.

688530581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2618250.

The product of its (nonzero) digits is 230400, while the sum is 44.

The square root of 688530581 is about 26239.8662534701. The cubic root of 688530581 is about 883.0278709170.

The spelling of 688530581 in words is "six hundred eighty-eight million, five hundred thirty thousand, five hundred eighty-one".