215581656016181 has 16 divisors (see below), whose sum is σ = 265332256468608. Its totient is φ = 170569466625600.

The previous prime is 215581656016169. The next prime is 215581656016193. The reversal of 215581656016181 is 181610656185512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (215581656016169) and next prime (215581656016193).

It is a de Polignac number, because none of the positive numbers 2^k-215581656016181 is a prime.

It is a super-2 number, since 2×215581656016181² (a number of 29 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215581656016141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20974511 + ... + 29514291.

It is an arithmetic number, because the mean of its divisors is an integer number (16583266029288).

Almost surely, 2^{215581656016181} is an apocalyptic number.

It is an amenable number.

215581656016181 is a deficient number, since it is larger than the sum of its proper divisors (49750600452427).

215581656016181 is a wasteful number, since it uses less digits than its factorization.

215581656016181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8817212.

The product of its (nonzero) digits is 3456000, while the sum is 56.

The spelling of 215581656016181 in words is "two hundred fifteen trillion, five hundred eighty-one billion, six hundred fifty-six million, sixteen thousand, one hundred eighty-one".