20665015021015 has 4 divisors (see below), whose sum is σ = 24798018025224. Its totient is φ = 16532012016808.

The previous prime is 20665015021003. The next prime is 20665015021081. The reversal of 20665015021015 is 51012051056602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20665015021015 - 2¹⁷ = 20665014889943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2066501502097 + ... + 2066501502106.

It is an arithmetic number, because the mean of its divisors is an integer number (6199504506306).

Almost surely, 2^{20665015021015} is an apocalyptic number.

20665015021015 is a deficient number, since it is larger than the sum of its proper divisors (4133003004209).

20665015021015 is an equidigital number, since it uses as much as digits as its factorization.

20665015021015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4133003004208.

The product of its (nonzero) digits is 18000, while the sum is 34.

Adding to 20665015021015 its reverse (51012051056602), we get a palindrome (71677066077617).

The spelling of 20665015021015 in words is "twenty trillion, six hundred sixty-five billion, fifteen million, twenty-one thousand, fifteen".