216281505661 has 8 divisors (see below), whose sum is σ = 237874258944. Its totient is φ = 195396711600.

The previous prime is 216281505647. The next prime is 216281505667. The reversal of 216281505661 is 166505182612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216281505661 - 2⁹ = 216281505149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216281505667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176989165 + ... + 176990386.

It is an arithmetic number, because the mean of its divisors is an integer number (29734282368).

Almost surely, 2^216281505661 is an apocalyptic number.

It is an amenable number.

216281505661 is a deficient number, since it is larger than the sum of its proper divisors (21592753283).

216281505661 is a wasteful number, since it uses less digits than its factorization.

216281505661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353979611.

The product of its (nonzero) digits is 172800, while the sum is 43.

The spelling of 216281505661 in words is "two hundred sixteen billion, two hundred eighty-one million, five hundred five thousand, six hundred sixty-one".