20688000 has 128 divisors (see below), whose sum is σ = 68739840. Its totient is φ = 5504000.

The previous prime is 20687993. The next prime is 20688001. The reversal of 20688000 is 88602.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20688001) 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 15 ways as a sum of consecutive naturals, for example, 47785 + ... + 48215.

It is an arithmetic number, because the mean of its divisors is an integer number (537030).

Almost surely, 2^20688000 is an apocalyptic number.

20688000 is a gapful number since it is divisible by the number (20) 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 20688000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34369920).

20688000 is an abundant number, since it is smaller than the sum of its proper divisors (48051840).

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

20688000 is an equidigital number, since it uses as much as digits as its factorization.

20688000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463 (or 441 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 20688000 is about 4548.4063143039. The cubic root of 20688000 is about 274.5192703151.

The spelling of 20688000 in words is "twenty million, six hundred eighty-eight thousand".