81267811 has 4 divisors (see below), whose sum is σ = 81289224. Its totient is φ = 81246400.

The previous prime is 81267793. The next prime is 81267817. The reversal of 81267811 is 11876218.

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 81267811 - 2⁹ = 81267299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81267817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3310 + ... + 13171.

It is an arithmetic number, because the mean of its divisors is an integer number (20322306).

Almost surely, 2^81267811 is an apocalyptic number.

81267811 is a deficient number, since it is larger than the sum of its proper divisors (21413).

81267811 is a wasteful number, since it uses less digits than its factorization.

81267811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21412.

The product of its digits is 5376, while the sum is 34.

The square root of 81267811 is about 9014.8661110413. The cubic root of 81267811 is about 433.1511987370.

The spelling of 81267811 in words is "eighty-one million, two hundred sixty-seven thousand, eight hundred eleven".