20442009 has 16 divisors (see below), whose sum is σ = 32504832. Its totient is φ = 11173008.

The previous prime is 20441999. The next prime is 20442011. The reversal of 20442009 is 90024402.

It is not a de Polignac number, because 20442009 - 2¹⁹ = 19917721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (20443009) 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, 20679 + ... + 21644.

It is an arithmetic number, because the mean of its divisors is an integer number (2031552).

Almost surely, 2^20442009 is an apocalyptic number.

It is an amenable number.

20442009 is a deficient number, since it is larger than the sum of its proper divisors (12062823).

20442009 is a wasteful number, since it uses less digits than its factorization.

20442009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42356.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 20442009 is about 4521.2839990427. The cubic root of 20442009 is about 273.4268704592.

The spelling of 20442009 in words is "twenty million, four hundred forty-two thousand, nine".