21365506615065 has 16 divisors (see below), whose sum is σ = 34184937494400. Its totient is φ = 11394894557952.

The previous prime is 21365506615043. The next prime is 21365506615091. The reversal of 21365506615065 is 56051660556312.

It is a de Polignac number, because none of the positive numbers 2^k-21365506615065 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21365506614999 and 21365506615017.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1768716 + ... + 6771954.

It is an arithmetic number, because the mean of its divisors is an integer number (2136558593400).

Almost surely, 2^{21365506615065} is an apocalyptic number.

It is an amenable number.

21365506615065 is a deficient number, since it is larger than the sum of its proper divisors (12819430879335).

21365506615065 is a wasteful number, since it uses less digits than its factorization.

21365506615065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5287936.

The product of its (nonzero) digits is 4860000, while the sum is 51.

The spelling of 21365506615065 in words is "twenty-one trillion, three hundred sixty-five billion, five hundred six million, six hundred fifteen thousand, sixty-five".