2155120015 has 4 divisors (see below), whose sum is σ = 2586144024. Its totient is φ = 1724096008.

The previous prime is 2155120001. The next prime is 2155120027. The reversal of 2155120015 is 5100215512.

It is a happy number.

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 2155120015 - 2¹⁹ = 2154595727 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 215511997 + ... + 215512006.

It is an arithmetic number, because the mean of its divisors is an integer number (646536006).

Almost surely, 2^2155120015 is an apocalyptic number.

2155120015 is a deficient number, since it is larger than the sum of its proper divisors (431024009).

2155120015 is an equidigital number, since it uses as much as digits as its factorization.

2155120015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431024008.

The product of its (nonzero) digits is 500, while the sum is 22.

The square root of 2155120015 is about 46423.2701885595. The cubic root of 2155120015 is about 1291.6865976714.

Adding to 2155120015 its reverse (5100215512), we get a palindrome (7255335527).

The spelling of 2155120015 in words is "two billion, one hundred fifty-five million, one hundred twenty thousand, fifteen".