688485121 has 9 divisors (see below), whose sum is σ = 727154883. Its totient is φ = 651776760.

The previous prime is 688485113. The next prime is 688485137. The reversal of 688485121 is 121584886.

The square root of 688485121 is 26239.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 312900721 + 375584400 = 17689^2 + 19380^2 .

It is not a de Polignac number, because 688485121 - 2³ = 688485113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688485191) 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 8 ways as a sum of consecutive naturals, for example, 497851 + ... + 499231.

It is an arithmetic number, because the mean of its divisors is an integer number (80794987).

Almost surely, 2^688485121 is an apocalyptic number.

688485121 is the 26239-th square number.

688485121 is the 13120-th centered octagonal number.

It is an amenable number.

688485121 is a deficient number, since it is larger than the sum of its proper divisors (38669762).

688485121 is an frugal number, since it uses more digits than its factorization.

688485121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2800 (or 1400 counting only the distinct ones).

The product of its digits is 122880, while the sum is 43.

The cubic root of 688485121 is about 883.0084366166.

It can be divided in two parts, 688 and 485121, that added together give a square (485809 = 697²).

The spelling of 688485121 in words is "six hundred eighty-eight million, four hundred eighty-five thousand, one hundred twenty-one".