216958494299121 has 9 divisors (see below), whose sum is σ = 313384555593291. Its totient is φ = 144638966740392.

The previous prime is 216958494299111. The next prime is 216958494299201. The reversal of 216958494299121 is 121992494859612.

It is a happy number.

The square root of 216958494299121 is 14729511.

It is a perfect power (a square), and thus also a powerful number.

216958494299121 is a `hidden beast` number, since 2 + 1 + 6 + 9 + 5 + 8 + 494 + 2 + 9 + 9 + 121 = 666.

It can be written as a sum of positive squares in only one way, i.e., 213207160608225 + 3751333690896 = 14601615^2 + 1936836^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 216958494299121 - 2¹⁹ = 216958493774833 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216958494299121.

It is not an unprimeable number, because it can be changed into a prime (216958494299111) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 41733615 + ... + 46643451.

Almost surely, 2^{216958494299121} is an apocalyptic number.

216958494299121 is the 14729511-st square number.

216958494299121 is the 7364756-th centered octagonal number.

It is an amenable number.

216958494299121 is a deficient number, since it is larger than the sum of its proper divisors (96426061294170).

216958494299121 is an frugal number, since it uses more digits than its factorization.

216958494299121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9819680 (or 4909840 counting only the distinct ones).

The product of its digits is 201553920, while the sum is 72.

The spelling of 216958494299121 in words is "two hundred sixteen trillion, nine hundred fifty-eight billion, four hundred ninety-four million, two hundred ninety-nine thousand, one hundred twenty-one".