81249268811 has 4 divisors (see below), whose sum is σ = 81305265624. Its totient is φ = 81193272000.

The previous prime is 81249268781. The next prime is 81249268823. The reversal of 81249268811 is 11886294218.

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 81249268811 - 2¹⁰ = 81249267787 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81249268811.

It is not an unprimeable number, because it can be changed into a prime (81249268211) 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, 27996230 + ... + 27999131.

It is an arithmetic number, because the mean of its divisors is an integer number (20326316406).

Almost surely, 2^81249268811 is an apocalyptic number.

81249268811 is a deficient number, since it is larger than the sum of its proper divisors (55996813).

81249268811 is a wasteful number, since it uses less digits than its factorization.

81249268811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55996812.

The product of its digits is 442368, while the sum is 50.

The spelling of 81249268811 in words is "eighty-one billion, two hundred forty-nine million, two hundred sixty-eight thousand, eight hundred eleven".