1688821680 has 320 divisors, whose sum is σ = 6569579520. Its totient is φ = 349360128.

The previous prime is 1688821649. The next prime is 1688821709. The reversal of 1688821680 is 861288861.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1156791 + ... + 1158249.

It is an arithmetic number, because the mean of its divisors is an integer number (20529936).

Almost surely, 2^1688821680 is an apocalyptic number.

1688821680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1688821680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3284789760).

1688821680 is an abundant number, since it is smaller than the sum of its proper divisors (4880757840).

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

1688821680 is a wasteful number, since it uses less digits than its factorization.

1688821680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1548 (or 1542 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 48.

The square root of 1688821680 is about 41095.2756408812. The cubic root of 1688821680 is about 1190.8615280459.

The spelling of 1688821680 in words is "one billion, six hundred eighty-eight million, eight hundred twenty-one thousand, six hundred eighty".