20013520 has 20 divisors (see below), whose sum is σ = 46531620. Its totient is φ = 8005376.

The previous prime is 20013491. The next prime is 20013523. The reversal of 20013520 is 2531002.

It can be written as a sum of positive squares in 2 ways, for example, as 15586704 + 4426816 = 3948^2 + 2104^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 20013520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20013523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125005 + ... + 125164.

It is an arithmetic number, because the mean of its divisors is an integer number (2326581).

Almost surely, 2^20013520 is an apocalyptic number.

20013520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20013520 is an abundant number, since it is smaller than the sum of its proper divisors (26518100).

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

20013520 is a wasteful number, since it uses less digits than its factorization.

20013520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250182 (or 250176 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 20013520 is about 4473.6472815813. The cubic root of 20013520 is about 271.5029127591.

Adding to 20013520 its reverse (2531002), we get a palindrome (22544522).

The spelling of 20013520 in words is "twenty million, thirteen thousand, five hundred twenty".