21516165705015 has 12 divisors (see below), whose sum is σ = 37294687222104. Its totient is φ = 11475288375984.

The previous prime is 21516165704983. The next prime is 21516165705059. The reversal of 21516165705015 is 51050756161512.

21516165705015 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 6 + 16 + 570 + 50 + 15 = 666.

It is not a de Polignac number, because 21516165705015 - 2⁵ = 21516165704983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 478137015667 = 21516165705015 / (2 + 1 + 5 + 1 + 6 + 1 + 6 + 5 + 7 + 0 + 5 + 0 + 1 + 5).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239068507789 + ... + 239068507878.

It is an arithmetic number, because the mean of its divisors is an integer number (3107890601842).

Almost surely, 2^{21516165705015} is an apocalyptic number.

21516165705015 is a deficient number, since it is larger than the sum of its proper divisors (15778521517089).

21516165705015 is a wasteful number, since it uses less digits than its factorization.

21516165705015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478137015678 (or 478137015675 counting only the distinct ones).

The product of its (nonzero) digits is 315000, while the sum is 45.

The spelling of 21516165705015 in words is "twenty-one trillion, five hundred sixteen billion, one hundred sixty-five million, seven hundred five thousand, fifteen".