20391104 has 56 divisors (see below), whose sum is σ = 43738800. Its totient is φ = 9400320.

The previous prime is 20391103. The next prime is 20391121. The reversal of 20391104 is 40119302.

It is not an unprimeable number, because it can be changed into a prime (20391101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49652 + ... + 50060.

It is an arithmetic number, because the mean of its divisors is an integer number (781050).

Almost surely, 2^20391104 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 20391104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21869400).

20391104 is an abundant number, since it is smaller than the sum of its proper divisors (23347696).

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

20391104 is a wasteful number, since it uses less digits than its factorization.

20391104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 471 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 20391104 is about 4515.6510051154. The cubic root of 20391104 is about 273.1997178923.

The spelling of 20391104 in words is "twenty million, three hundred ninety-one thousand, one hundred four".