20643800 has 48 divisors (see below), whose sum is σ = 48311640. Its totient is φ = 8203520.

The previous prime is 20643769. The next prime is 20643809. The reversal of 20643800 is 834602.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 46379 + ... + 46821.

Almost surely, 2^20643800 is an apocalyptic number.

20643800 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 20643800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24155820).

20643800 is an abundant number, since it is smaller than the sum of its proper divisors (27667840).

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

20643800 is a wasteful number, since it uses less digits than its factorization.

20643800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692 (or 683 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 20643800 is about 4543.5448715733. The cubic root of 20643800 is about 274.3236270551.

The spelling of 20643800 in words is "twenty million, six hundred forty-three thousand, eight hundred".