81218311141 has 4 divisors (see below), whose sum is σ = 88601793984. Its totient is φ = 73834828300.

The previous prime is 81218311129. The next prime is 81218311171. The reversal of 81218311141 is 14111381218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81218311141 - 2¹⁵ = 81218278373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81218311171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3691741405 + ... + 3691741426.

It is an arithmetic number, because the mean of its divisors is an integer number (22150448496).

Almost surely, 2^81218311141 is an apocalyptic number.

It is an amenable number.

81218311141 is a deficient number, since it is larger than the sum of its proper divisors (7383482843).

81218311141 is a wasteful number, since it uses less digits than its factorization.

81218311141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7383482842.

The product of its digits is 1536, while the sum is 31.

Adding to 81218311141 its reverse (14111381218), we get a palindrome (95329692359).

The spelling of 81218311141 in words is "eighty-one billion, two hundred eighteen million, three hundred eleven thousand, one hundred forty-one".