81120215811 has 8 divisors (see below), whose sum is σ = 109375572240. Its totient is φ = 53472501632.

The previous prime is 81120215801. The next prime is 81120215843. The reversal of 81120215811 is 11851202118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81120215811 - 2¹⁷ = 81120084739 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81120215801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151910250 + ... + 151910783.

It is an arithmetic number, because the mean of its divisors is an integer number (13671946530).

Almost surely, 2^81120215811 is an apocalyptic number.

81120215811 is a deficient number, since it is larger than the sum of its proper divisors (28255356429).

81120215811 is a wasteful number, since it uses less digits than its factorization.

81120215811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303821125.

The product of its (nonzero) digits is 1280, while the sum is 30.

Adding to 81120215811 its reverse (11851202118), we get a palindrome (92971417929).

The spelling of 81120215811 in words is "eighty-one billion, one hundred twenty million, two hundred fifteen thousand, eight hundred eleven".