20001015 has 48 divisors (see below), whose sum is σ = 36972000.
Its totient is φ = 9974016.
The previous prime is 20001001. The next prime is 20001019. The reversal of 20001015 is 51010002.
Adding to 20001015 its reverse (51010002), we get a palindrome (71011017).
It is a happy number.
It is not a de Polignac number, because 20001015 - 26 = 20000951 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a junction number, because it is equal to n+sod(n) for n = 20000988 and 20001006.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20001019) by changing a digit.
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 47 ways as a sum of consecutive naturals, for example, 127317 + ... + 127473.
It is an arithmetic number, because the mean of its divisors is an integer number (770250).
It is the magic constant of a 342 × 342 magic square.
Almost surely, 220001015 is an apocalyptic number.
20001015 is a deficient number, since it is larger than the sum of its proper divisors (16970985).
20001015 is a wasteful number, since it uses less digits than its factorization.
20001015 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 336 (or 333 counting only the distinct ones).
The product of its (nonzero) digits is 10, while the sum is 9.
The square root of 20001015 is about 4472.2494340097.
The cubic root of 20001015 is about 271.4463534716.
The spelling of 20001015 in words is "twenty million, one thousand, fifteen".