20800000 has 120 divisors (see below), whose sum is σ = 55941732. Its totient is φ = 7680000.

The previous prime is 20799983. The next prime is 20800007. The reversal of 20800000 is 802.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 5683456 + 15116544 = 2384^2 + 3888^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a self number, because there is not a number n which added to its sum of digits gives 20800000.

It is not an unprimeable number, because it can be changed into a prime (20800007) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1599994 + ... + 1600006.

Almost surely, 2^20800000 is an apocalyptic number.

20800000 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 20800000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27970866).

20800000 is an abundant number, since it is smaller than the sum of its proper divisors (35141732).

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

20800000 is an frugal number, since it uses more digits than its factorization.

20800000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56 (or 20 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 20800000 is about 4560.7017003966. The cubic root of 20800000 is about 275.0137734148.

Adding to 20800000 its reverse (802), we get a palindrome (20800802).

It can be divided in two parts, 20 and 800000, that multiplied together give a square (16000000 = 4000²).

The spelling of 20800000 in words is "twenty million, eight hundred thousand".