81436811 has 2 divisors, whose sum is σ = 81436812. Its totient is φ = 81436810.

The previous prime is 81436807. The next prime is 81436819. The reversal of 81436811 is 11863418.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81436811 - 2² = 81436807 is a prime.

It is not a weakly prime, because it can be changed into another prime (81436819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40718405 + 40718406.

It is an arithmetic number, because the mean of its divisors is an integer number (40718406).

Almost surely, 2^81436811 is an apocalyptic number.

81436811 is a deficient number, since it is larger than the sum of its proper divisors (1).

81436811 is an equidigital number, since it uses as much as digits as its factorization.

81436811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 32.

The square root of 81436811 is about 9024.2346489882. The cubic root of 81436811 is about 433.4512431933.

The spelling of 81436811 in words is "eighty-one million, four hundred thirty-six thousand, eight hundred eleven".