20009000 has 128 divisors (see below), whose sum is σ = 54587520. Its totient is φ = 6784000.

The previous prime is 20008999. The next prime is 20009029. The reversal of 20009000 is 90002.

20009000 = T₃₂₁ + T₃₂₂ + ... + T₅₃₄.

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

20009000 is a modest number, since divided by 9000 gives 2000 as remainder.

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, 186947 + ... + 187053.

It is an arithmetic number, because the mean of its divisors is an integer number (426465).

Almost surely, 2^20009000 is an apocalyptic number.

20009000 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 20009000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27293760).

20009000 is an abundant number, since it is smaller than the sum of its proper divisors (34578520).

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

20009000 is a wasteful number, since it uses less digits than its factorization.

20009000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 142 counting only the distinct ones).

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

The square root of 20009000 is about 4473.1420724140. The cubic root of 20009000 is about 271.4824718178.

Adding to 20009000 its reverse (90002), we get a palindrome (20099002).

The spelling of 20009000 in words is "twenty million, nine thousand".