20290209 has 16 divisors (see below), whose sum is σ = 28424832. Its totient is φ = 12849408.

The previous prime is 20290183. The next prime is 20290211. The reversal of 20290209 is 90209202.

It is not a de Polignac number, because 20290209 - 2¹⁷ = 20159137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20290009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9897 + ... + 11769.

It is an arithmetic number, because the mean of its divisors is an integer number (1776552).

Almost surely, 2^20290209 is an apocalyptic number.

It is an amenable number.

20290209 is a deficient number, since it is larger than the sum of its proper divisors (8134623).

20290209 is a wasteful number, since it uses less digits than its factorization.

20290209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2056.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 20290209 is about 4504.4654510830. The cubic root of 20290209 is about 272.7483760741.

The spelling of 20290209 in words is "twenty million, two hundred ninety thousand, two hundred nine".