688270405 has 4 divisors (see below), whose sum is σ = 825924492. Its totient is φ = 550616320.

The previous prime is 688270393. The next prime is 688270409. The reversal of 688270405 is 504072886.

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 459716481 + 228553924 = 21441^2 + 15118^2 .

It is a de Polignac number, because none of the positive numbers 2^k-688270405 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688270409) 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, 68827036 + ... + 68827045.

It is an arithmetic number, because the mean of its divisors is an integer number (206481123).

Almost surely, 2^688270405 is an apocalyptic number.

It is an amenable number.

688270405 is a deficient number, since it is larger than the sum of its proper divisors (137654087).

688270405 is a wasteful number, since it uses less digits than its factorization.

688270405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137654086.

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 688270405 is about 26234.9081378228. The cubic root of 688270405 is about 882.9166332516.

The spelling of 688270405 in words is "six hundred eighty-eight million, two hundred seventy thousand, four hundred five".