20100520 has 48 divisors (see below), whose sum is σ = 49723380. Its totient is φ = 7307520.

The previous prime is 20100497. The next prime is 20100527. The reversal of 20100520 is 2500102.

It can be written as a sum of positive squares in 2 ways, for example, as 16924996 + 3175524 = 4114^2 + 1782^2 .

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 = 20100497 and 20100506.

It is not an unprimeable number, because it can be changed into a prime (20100527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2764 + ... + 6916.

Almost surely, 2^20100520 is an apocalyptic number.

20100520 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 20100520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24861690).

20100520 is an abundant number, since it is smaller than the sum of its proper divisors (29622860).

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

20100520 is a wasteful number, since it uses less digits than its factorization.

20100520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4186 (or 4171 counting only the distinct ones).

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

The square root of 20100520 is about 4483.3603468827. The cubic root of 20100520 is about 271.8957573441.

Adding to 20100520 its reverse (2500102), we get a palindrome (22600622).

The spelling of 20100520 in words is "twenty million, one hundred thousand, five hundred twenty".