21660560652655 has 16 divisors (see below), whose sum is σ = 26556869770560. Its totient is φ = 16954138659328.

The previous prime is 21660560652649. The next prime is 21660560652719. The reversal of 21660560652655 is 55625606506612.

It is a cyclic number.

It is not a de Polignac number, because 21660560652655 - 2¹⁹ = 21660560128367 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21660560652596 and 21660560652605.

It is a congruent number.

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, 113746042 + ... + 113936311.

It is an arithmetic number, because the mean of its divisors is an integer number (1659804360660).

Almost surely, 2^{21660560652655} is an apocalyptic number.

21660560652655 is a deficient number, since it is larger than the sum of its proper divisors (4896309117905).

21660560652655 is a wasteful number, since it uses less digits than its factorization.

21660560652655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227682770.

The product of its (nonzero) digits is 19440000, while the sum is 55.

The spelling of 21660560652655 in words is "twenty-one trillion, six hundred sixty billion, five hundred sixty million, six hundred fifty-two thousand, six hundred fifty-five".