20001520 has 160 divisors (see below), whose sum is σ = 61710336. Its totient is φ = 5836800.

The previous prime is 20001517. The next prime is 20001521. The reversal of 20001520 is 2510002.

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 = 20001497 and 20001506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104625 + ... + 104815.

Almost surely, 2^20001520 is an apocalyptic number.

20001520 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 20001520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30855168).

20001520 is an abundant number, since it is smaller than the sum of its proper divisors (41708816).

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

20001520 is a wasteful number, since it uses less digits than its factorization.

20001520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239 (or 233 counting only the distinct ones).

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

The square root of 20001520 is about 4472.3058929371. The cubic root of 20001520 is about 271.4486380099.

Adding to 20001520 its reverse (2510002), we get a palindrome (22511522).

The spelling of 20001520 in words is "twenty million, one thousand, five hundred twenty".