20900000 has 144 divisors (see below), whose sum is σ = 59058720. Its totient is φ = 7200000.

The previous prime is 20899993. The next prime is 20900051. The reversal of 20900000 is 902.

It is a Harshad number since it is a multiple of its sum of digits (11).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1099991 + ... + 1100009.

It is an arithmetic number, because the mean of its divisors is an integer number (410130).

Almost surely, 2^20900000 is an apocalyptic number.

20900000 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 20900000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29529360).

20900000 is an abundant number, since it is smaller than the sum of its proper divisors (38158720).

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

20900000 is an equidigital number, since it uses as much as digits as its factorization.

20900000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 37 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 20900000 is about 4571.6517802650. The cubic root of 20900000 is about 275.4537962027.

Adding to 20900000 its reverse (902), we get a palindrome (20900902).

The spelling of 20900000 in words is "twenty million, nine hundred thousand".