688505081 has 4 divisors (see below), whose sum is σ = 751096464. Its totient is φ = 625913700.

The previous prime is 688505057. The next prime is 688505101. The reversal of 688505081 is 180505886.

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 not a de Polignac number, because 688505081 - 2⁶ = 688505017 is a prime.

It is a super-2 number, since 2×688505081² = 948078493125633122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688505281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31295675 + ... + 31295696.

It is an arithmetic number, because the mean of its divisors is an integer number (187774116).

Almost surely, 2^688505081 is an apocalyptic number.

It is an amenable number.

688505081 is a deficient number, since it is larger than the sum of its proper divisors (62591383).

688505081 is a wasteful number, since it uses less digits than its factorization.

688505081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62591382.

The product of its (nonzero) digits is 76800, while the sum is 41.

The square root of 688505081 is about 26239.3803471042. The cubic root of 688505081 is about 883.0169696880.

The spelling of 688505081 in words is "six hundred eighty-eight million, five hundred five thousand, eighty-one".