20890000 has 50 divisors (see below), whose sum is σ = 50600990. Its totient is φ = 8352000.

The previous prime is 20889943. The next prime is 20890019. The reversal of 20890000 is 9802.

It can be written as a sum of positive squares in 5 ways, for example, as 4112784 + 16777216 = 2028^2 + 4096^2 .

It is a tau number, because it is divible by the number of its divisors (50).

It is a self number, because there is not a number n which added to its sum of digits gives 20890000.

It is an unprimeable number.

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 9 ways as a sum of consecutive naturals, for example, 8956 + ... + 11044.

Almost surely, 2^20890000 is an apocalyptic number.

20890000 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 20890000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25300495).

20890000 is an abundant number, since it is smaller than the sum of its proper divisors (29710990).

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

20890000 is an equidigital number, since it uses as much as digits as its factorization.

20890000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2117 (or 2096 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20890000 is about 4570.5579528106. The cubic root of 20890000 is about 275.4098571692.

Adding to 20890000 its reverse (9802), we get a palindrome (20899802).

The spelling of 20890000 in words is "twenty million, eight hundred ninety thousand".