81764071 has 2 divisors, whose sum is σ = 81764072. Its totient is φ = 81764070.

The previous prime is 81764017. The next prime is 81764083. The reversal of 81764071 is 17046718.

Together with previous prime (81764017) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81764071 - 2²¹ = 79666919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81764171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40882035 + 40882036.

It is an arithmetic number, because the mean of its divisors is an integer number (40882036).

Almost surely, 2^81764071 is an apocalyptic number.

81764071 is a deficient number, since it is larger than the sum of its proper divisors (1).

81764071 is an equidigital number, since it uses as much as digits as its factorization.

81764071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 81764071 is about 9042.3487546102. The cubic root of 81764071 is about 434.0310860671.

The spelling of 81764071 in words is "eighty-one million, seven hundred sixty-four thousand, seventy-one".