81081019 has 2 divisors, whose sum is σ = 81081020. Its totient is φ = 81081018.

The previous prime is 81081001. The next prime is 81081029. The reversal of 81081019 is 91018018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81081019 - 2⁷ = 81080891 is a prime.

It is a super-2 number, since 2×81081019² = 13148263284156722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81081029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40540509 + 40540510.

It is an arithmetic number, because the mean of its divisors is an integer number (40540510).

Almost surely, 2^81081019 is an apocalyptic number.

81081019 is a deficient number, since it is larger than the sum of its proper divisors (1).

81081019 is an equidigital number, since it uses as much as digits as its factorization.

81081019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 28.

The square root of 81081019 is about 9004.4999305903. The cubic root of 81081019 is about 432.8190818090.

The spelling of 81081019 in words is "eighty-one million, eighty-one thousand, nineteen".