21517266477561 has 16 divisors (see below), whose sum is σ = 28791370814400. Its totient is φ = 14294087198720.

The previous prime is 21517266477521. The next prime is 21517266477617. The reversal of 21517266477561 is 16577466271512.

It is a cyclic number.

It is not a de Polignac number, because 21517266477561 - 2⁷ = 21517266477433 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21517266477495 and 21517266477504.

It is not an unprimeable number, because it can be changed into a prime (21517266477521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9470475 + ... + 11520608.

It is an arithmetic number, because the mean of its divisors is an integer number (1799460675900).

Almost surely, 2^{21517266477561} is an apocalyptic number.

It is an amenable number.

21517266477561 is a deficient number, since it is larger than the sum of its proper divisors (7274104336839).

21517266477561 is a wasteful number, since it uses less digits than its factorization.

21517266477561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20992296.

The product of its digits is 29635200, while the sum is 60.

The spelling of 21517266477561 in words is "twenty-one trillion, five hundred seventeen billion, two hundred sixty-six million, four hundred seventy-seven thousand, five hundred sixty-one".