216561205215 has 24 divisors (see below), whose sum is σ = 384528192048. Its totient is φ = 112682252160.

The previous prime is 216561205181. The next prime is 216561205229. The reversal of 216561205215 is 512502165612.

216561205215 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 6 + 120 + 521 + 5 = 666.

It is not a de Polignac number, because 216561205215 - 2¹² = 216561201119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216561205215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58686829 + ... + 58690518.

It is an arithmetic number, because the mean of its divisors is an integer number (16022008002).

Almost surely, 2^216561205215 is an apocalyptic number.

216561205215 is a deficient number, since it is larger than the sum of its proper divisors (167966986833).

216561205215 is a wasteful number, since it uses less digits than its factorization.

216561205215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117377399 (or 117377396 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 216561205215 in words is "two hundred sixteen billion, five hundred sixty-one million, two hundred five thousand, two hundred fifteen".