20509000 has 32 divisors (see below), whose sum is σ = 47993400. Its totient is φ = 8203200.

The previous prime is 20508997. The next prime is 20509057. The reversal of 20509000 is 90502.

It can be written as a sum of positive squares in 4 ways, for example, as 3319684 + 17189316 = 1822^2 + 4146^2 .

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 7 ways as a sum of consecutive naturals, for example, 9255 + ... + 11254.

Almost surely, 2^20509000 is an apocalyptic number.

20509000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20509000 is an abundant number, since it is smaller than the sum of its proper divisors (27484400).

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

20509000 is a wasteful number, since it uses less digits than its factorization.

20509000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20530 (or 20516 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 20509000 is about 4528.6863437425. The cubic root of 20509000 is about 273.7252293705.

Adding to 20509000 its reverse (90502), we get a palindrome (20599502).

The spelling of 20509000 in words is "twenty million, five hundred nine thousand".