20105020 has 48 divisors (see below), whose sum is σ = 46357920. Its totient is φ = 7278336.

The previous prime is 20105009. The next prime is 20105039. The reversal of 20105020 is 2050102.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 20104988 and 20105006.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 13051 + ... + 14509.

It is an arithmetic number, because the mean of its divisors is an integer number (965790).

Almost surely, 2^20105020 is an apocalyptic number.

20105020 is a gapful number since it is divisible by the number (20) 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 20105020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23178960).

20105020 is an abundant number, since it is smaller than the sum of its proper divisors (26252900).

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

20105020 is a wasteful number, since it uses less digits than its factorization.

20105020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534 (or 1532 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 20105020 is about 4483.8621745098. The cubic root of 20105020 is about 271.9160460334.

Adding to 20105020 its reverse (2050102), we get a palindrome (22155122).

The spelling of 20105020 in words is "twenty million, one hundred five thousand, twenty".