688620385 has 4 divisors (see below), whose sum is σ = 826344468. Its totient is φ = 550896304.

The previous prime is 688620371. The next prime is 688620419. The reversal of 688620385 is 583026886.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 504990784 + 183629601 = 22472^2 + 13551^2 .

It is a cyclic number.

It is not a de Polignac number, because 688620385 - 2⁹ = 688619873 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68862034 + ... + 68862043.

It is an arithmetic number, because the mean of its divisors is an integer number (206586117).

Almost surely, 2^688620385 is an apocalyptic number.

It is an amenable number.

688620385 is a deficient number, since it is larger than the sum of its proper divisors (137724083).

688620385 is a wasteful number, since it uses less digits than its factorization.

688620385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137724082.

The product of its (nonzero) digits is 552960, while the sum is 46.

The square root of 688620385 is about 26241.5774106665. The cubic root of 688620385 is about 883.0662599103.

The spelling of 688620385 in words is "six hundred eighty-eight million, six hundred twenty thousand, three hundred eighty-five".