81181464511 has 4 divisors (see below), whose sum is σ = 92778816592. Its totient is φ = 69584112432.

The previous prime is 81181464509. The next prime is 81181464527. The reversal of 81181464511 is 11546418118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81181464511 - 2¹ = 81181464509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81181461511) 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, 5798676030 + ... + 5798676043.

It is an arithmetic number, because the mean of its divisors is an integer number (23194704148).

Almost surely, 2^81181464511 is an apocalyptic number.

81181464511 is a deficient number, since it is larger than the sum of its proper divisors (11597352081).

81181464511 is a wasteful number, since it uses less digits than its factorization.

81181464511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11597352080.

The product of its digits is 30720, while the sum is 40.

The spelling of 81181464511 in words is "eighty-one billion, one hundred eighty-one million, four hundred sixty-four thousand, five hundred eleven".