81099228371121 has 9 divisors (see below), whose sum is σ = 117143368893291. Its totient is φ = 54066134236392.

The previous prime is 81099228371113. The next prime is 81099228371149. The reversal of 81099228371121 is 12117382299018.

The square root of 81099228371121 is 9005511.

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

It can be written as a sum of positive squares in only one way, i.e., 80508537749025 + 590690622096 = 8972655^2 + 768564^2 .

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

It is not a de Polignac number, because 81099228371121 - 2³ = 81099228371113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81099228372121) 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, 25515615 + ... + 28517451.

Almost surely, 2^{81099228371121} is an apocalyptic number.

81099228371121 is the 9005511-st square number.

81099228371121 is the 4502756-th centered octagonal number.

It is an amenable number.

81099228371121 is a deficient number, since it is larger than the sum of its proper divisors (36044140522170).

81099228371121 is an frugal number, since it uses more digits than its factorization.

81099228371121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6003680 (or 3001840 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 54.

The spelling of 81099228371121 in words is "eighty-one trillion, ninety-nine billion, two hundred twenty-eight million, three hundred seventy-one thousand, one hundred twenty-one".