21616555562811 has 96 divisors (see below), whose sum is σ = 35415934444800. Its totient is φ = 13066893665280.

The previous prime is 21616555562809. The next prime is 21616555562839. The reversal of 21616555562811 is 11826555561612.

21616555562811 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 6 + 5 + 5 + 5 + 5 + 628 + 1 + 1 = 666.

It is not a de Polignac number, because 21616555562811 - 2¹ = 21616555562809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21616555562851) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2177108095 + ... + 2177118023.

It is an arithmetic number, because the mean of its divisors is an integer number (368915983800).

Almost surely, 2^{21616555562811} is an apocalyptic number.

21616555562811 is a deficient number, since it is larger than the sum of its proper divisors (13799378881989).

21616555562811 is a wasteful number, since it uses less digits than its factorization.

21616555562811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11991 (or 11979 counting only the distinct ones).

The product of its digits is 4320000, while the sum is 54.

The spelling of 21616555562811 in words is "twenty-one trillion, six hundred sixteen billion, five hundred fifty-five million, five hundred sixty-two thousand, eight hundred eleven".