20871000 has 128 divisors (see below), whose sum is σ = 72446400. Its totient is φ = 5558400.

The previous prime is 20870939. The next prime is 20871001. The reversal of 20871000 is 17802.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20871001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26614 + ... + 27386.

Almost surely, 2^20871000 is an apocalyptic number.

20871000 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 20871000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36223200).

20871000 is an abundant number, since it is smaller than the sum of its proper divisors (51575400).

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

20871000 is a wasteful number, since it uses less digits than its factorization.

20871000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803 (or 783 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 20871000 is about 4568.4789591285. The cubic root of 20871000 is about 275.3263343586.

Adding to 20871000 its reverse (17802), we get a palindrome (20888802).

The spelling of 20871000 in words is "twenty million, eight hundred seventy-one thousand".