216721946061 has 40 divisors (see below), whose sum is σ = 338408161344. Its totient is φ = 137959303680.

The previous prime is 216721946053. The next prime is 216721946071. The reversal of 216721946061 is 160649127612.

216721946061 is a `hidden beast` number, since 2 + 16 + 7 + 21 + 9 + 4 + 606 + 1 = 666.

It is not a de Polignac number, because 216721946061 - 2³ = 216721946053 is a prime.

It is a super-3 number, since 3×216721946061³ (a number of 35 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 216721945998 and 216721946016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216721946011) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 974146 + ... + 1175756.

Almost surely, 2^216721946061 is an apocalyptic number.

It is an amenable number.

216721946061 is a deficient number, since it is larger than the sum of its proper divisors (121686215283).

216721946061 is a wasteful number, since it uses less digits than its factorization.

216721946061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202223 (or 202214 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 216721946061 in words is "two hundred sixteen billion, seven hundred twenty-one million, nine hundred forty-six thousand, sixty-one".