20005530 has 64 divisors (see below), whose sum is σ = 50232960. Its totient is φ = 5094144.

The previous prime is 20005529. The next prime is 20005541. The reversal of 20005530 is 3550002.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74236 + ... + 74504.

It is an arithmetic number, because the mean of its divisors is an integer number (784890).

Almost surely, 2^20005530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20005530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25116480).

20005530 is an abundant number, since it is smaller than the sum of its proper divisors (30227430).

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

20005530 is a wasteful number, since it uses less digits than its factorization.

20005530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383.

The product of its (nonzero) digits is 150, while the sum is 15.

The square root of 20005530 is about 4472.7541850632. The cubic root of 20005530 is about 271.4667772364.

Adding to 20005530 its reverse (3550002), we get a palindrome (23555532).

The spelling of 20005530 in words is "twenty million, five thousand, five hundred thirty".