21655364466605 has 16 divisors (see below), whose sum is σ = 26900673274800. Its totient is φ = 16715607713280.

The previous prime is 21655364466601. The next prime is 21655364466629. The reversal of 21655364466605 is 50666446355612.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 395352970441 + 21260011496164 = 628771^2 + 4610858^2 .

It is not a de Polignac number, because 21655364466605 - 2² = 21655364466601 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21655364466601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50206370 + ... + 50635859.

It is an arithmetic number, because the mean of its divisors is an integer number (1681292079675).

Almost surely, 2^{21655364466605} is an apocalyptic number.

It is an amenable number.

21655364466605 is a deficient number, since it is larger than the sum of its proper divisors (5245308808195).

21655364466605 is a wasteful number, since it uses less digits than its factorization.

21655364466605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100843744.

The product of its (nonzero) digits is 93312000, while the sum is 59.

The spelling of 21655364466605 in words is "twenty-one trillion, six hundred fifty-five billion, three hundred sixty-four million, four hundred sixty-six thousand, six hundred five".