688240221 has 8 divisors (see below), whose sum is σ = 919699200. Its totient is φ = 457804032.

The previous prime is 688240213. The next prime is 688240237. The reversal of 688240221 is 122042886.

It is a happy number.

688240221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 688240221 - 2³ = 688240213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688240271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 254125 + ... + 256818.

It is an arithmetic number, because the mean of its divisors is an integer number (114962400).

Almost surely, 2^688240221 is an apocalyptic number.

It is an amenable number.

688240221 is a deficient number, since it is larger than the sum of its proper divisors (231458979).

688240221 is a wasteful number, since it uses less digits than its factorization.

688240221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511395.

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 688240221 is about 26234.3328674468. The cubic root of 688240221 is about 882.9037263355.

The spelling of 688240221 in words is "six hundred eighty-eight million, two hundred forty thousand, two hundred twenty-one".