1688386720 has 24 divisors (see below), whose sum is σ = 3988814004. Its totient is φ = 675354624.

The previous prime is 1688386669. The next prime is 1688386723. The reversal of 1688386720 is 276838861.

It can be written as a sum of positive squares in 2 ways, for example, as 1670847376 + 17539344 = 40876^2 + 4188^2 .

It is not an unprimeable number, because it can be changed into a prime (1688386723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5276049 + ... + 5276368.

Almost surely, 2^1688386720 is an apocalyptic number.

1688386720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1688386720 is an abundant number, since it is smaller than the sum of its proper divisors (2300427284).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1688386720 is a wasteful number, since it uses less digits than its factorization.

1688386720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10552432 (or 10552424 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 49.

The square root of 1688386720 is about 41089.9832075897. The cubic root of 1688386720 is about 1190.7592828708.

The spelling of 1688386720 in words is "one billion, six hundred eighty-eight million, three hundred eighty-six thousand, seven hundred twenty".