20409136 has 40 divisors (see below), whose sum is σ = 43867728. Its totient is φ = 9120000.

The previous prime is 20409131. The next prime is 20409149. The reversal of 20409136 is 63190402.

It is a self number, because there is not a number n which added to its sum of digits gives 20409136.

It is not an unprimeable number, because it can be changed into a prime (20409131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9786 + ... + 11686.

Almost surely, 2^20409136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20409136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21933864).

20409136 is an abundant number, since it is smaller than the sum of its proper divisors (23458592).

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

20409136 is a wasteful number, since it uses less digits than its factorization.

20409136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1981 (or 1975 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 20409136 is about 4517.6471752451. The cubic root of 20409136 is about 273.2802249915.

Adding to 20409136 its reverse (63190402), we get a palindrome (83599538).

The spelling of 20409136 in words is "twenty million, four hundred nine thousand, one hundred thirty-six".