81529379 has 2 divisors, whose sum is σ = 81529380. Its totient is φ = 81529378.

The previous prime is 81529363. The next prime is 81529397. The reversal of 81529379 is 97392518.

Together with next prime (81529397) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81529379 - 2⁴ = 81529363 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81529879) 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 as a sum of consecutive naturals, namely, 40764689 + 40764690.

It is an arithmetic number, because the mean of its divisors is an integer number (40764690).

Almost surely, 2^81529379 is an apocalyptic number.

81529379 is a deficient number, since it is larger than the sum of its proper divisors (1).

81529379 is an equidigital number, since it uses as much as digits as its factorization.

81529379 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 44.

The square root of 81529379 is about 9029.3620483398. The cubic root of 81529379 is about 433.6154135118.

The spelling of 81529379 in words is "eighty-one million, five hundred twenty-nine thousand, three hundred seventy-nine".