20820015 has 12 divisors (see below), whose sum is σ = 36088104. Its totient is φ = 11103984.

The previous prime is 20820001. The next prime is 20820017. The reversal of 20820015 is 51002802.

It is not a de Polignac number, because 20820015 - 2¹² = 20815919 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20820015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20820017) 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, 231289 + ... + 231378.

It is an arithmetic number, because the mean of its divisors is an integer number (3007342).

Almost surely, 2^20820015 is an apocalyptic number.

20820015 is a deficient number, since it is larger than the sum of its proper divisors (15268089).

20820015 is a wasteful number, since it uses less digits than its factorization.

20820015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462678 (or 462675 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 20820015 is about 4562.8954623134. The cubic root of 20820015 is about 275.1019566851.

Adding to 20820015 its reverse (51002802), we get a palindrome (71822817).

The spelling of 20820015 in words is "twenty million, eight hundred twenty thousand, fifteen".