20509104 has 160 divisors (see below), whose sum is σ = 68567040. Its totient is φ = 5126400.

The previous prime is 20509081. The next prime is 20509109. The reversal of 20509104 is 40190502.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20509109) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 114487 + ... + 114665.

It is an arithmetic number, because the mean of its divisors is an integer number (428544).

Almost surely, 2^20509104 is an apocalyptic number.

20509104 is a gapful number since it is divisible by the number (24) 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 20509104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34283520).

20509104 is an abundant number, since it is smaller than the sum of its proper divisors (48057936).

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

20509104 is a wasteful number, since it uses less digits than its factorization.

20509104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 20509104 is about 4528.6978260864. The cubic root of 20509104 is about 273.7256920515.

Adding to 20509104 its reverse (40190502), we get a palindrome (60699606).

The spelling of 20509104 in words is "twenty million, five hundred nine thousand, one hundred four".