20643000 has 128 divisors (see below), whose sum is σ = 73681920. Its totient is φ = 4713600.

The previous prime is 20642971. The next prime is 20643043. The reversal of 20643000 is 34602.

It is a super-2 number, since 2×20643000² = 852266898000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20509 + ... + 21491.

It is an arithmetic number, because the mean of its divisors is an integer number (575640).

Almost surely, 2^20643000 is an apocalyptic number.

20643000 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 20643000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36840960).

20643000 is an abundant number, since it is smaller than the sum of its proper divisors (53038920).

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

20643000 is a wasteful number, since it uses less digits than its factorization.

20643000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1014 (or 1000 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 20643000 is about 4543.4568337335. The cubic root of 20643000 is about 274.3200834288.

Adding to 20643000 its reverse (34602), we get a palindrome (20677602).

The spelling of 20643000 in words is "twenty million, six hundred forty-three thousand".