20381504 has 112 divisors (see below), whose sum is σ = 50694336. Its totient is φ = 7987200.

The previous prime is 20381489. The next prime is 20381549. The reversal of 20381504 is 40518302.

It is a self number, because there is not a number n which added to its sum of digits gives 20381504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155519 + ... + 155649.

It is an arithmetic number, because the mean of its divisors is an integer number (452628).

Almost surely, 2^20381504 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 20381504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25347168).

20381504 is an abundant number, since it is smaller than the sum of its proper divisors (30312832).

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

20381504 is a wasteful number, since it uses less digits than its factorization.

20381504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 20381504 is about 4514.5879103192. The cubic root of 20381504 is about 273.1568376084.

Adding to 20381504 its reverse (40518302), we get a palindrome (60899806).

The spelling of 20381504 in words is "twenty million, three hundred eighty-one thousand, five hundred four".