688138825 has 24 divisors (see below), whose sum is σ = 962974080. Its totient is φ = 483201600.

The previous prime is 688138799. The next prime is 688138859. The reversal of 688138825 is 528831886.

It is a happy number.

It is not a de Polignac number, because 688138825 - 2²¹ = 686041673 is a prime.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35169 + ... + 51118.

It is an arithmetic number, because the mean of its divisors is an integer number (40123920).

Almost surely, 2^688138825 is an apocalyptic number.

It is an amenable number.

688138825 is a deficient number, since it is larger than the sum of its proper divisors (274835255).

688138825 is a wasteful number, since it uses less digits than its factorization.

688138825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86337 (or 86332 counting only the distinct ones).

The product of its digits is 737280, while the sum is 49.

The square root of 688138825 is about 26232.4002904805. The cubic root of 688138825 is about 882.8603658439.

The spelling of 688138825 in words is "six hundred eighty-eight million, one hundred thirty-eight thousand, eight hundred twenty-five".