688643245 has 4 divisors (see below), whose sum is σ = 826371900. Its totient is φ = 550914592.

The previous prime is 688643243. The next prime is 688643303. The reversal of 688643245 is 542346886.

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 392872041 + 295771204 = 19821^2 + 17198^2 .

It is a cyclic number.

It is not a de Polignac number, because 688643245 - 2¹ = 688643243 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 688643195 and 688643204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688643243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68864320 + ... + 68864329.

It is an arithmetic number, because the mean of its divisors is an integer number (206592975).

Almost surely, 2^688643245 is an apocalyptic number.

It is an amenable number.

688643245 is a deficient number, since it is larger than the sum of its proper divisors (137728655).

688643245 is a wasteful number, since it uses less digits than its factorization.

688643245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137728654.

The product of its digits is 1105920, while the sum is 46.

The square root of 688643245 is about 26242.0129753798. The cubic root of 688643245 is about 883.0760314631.

The spelling of 688643245 in words is "six hundred eighty-eight million, six hundred forty-three thousand, two hundred forty-five".