81097619 has 2 divisors, whose sum is σ = 81097620. Its totient is φ = 81097618.

The previous prime is 81097507. The next prime is 81097637. The reversal of 81097619 is 91679018.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81097619 - 2⁸ = 81097363 is a prime.

It is a super-2 number, since 2×81097619² = 13153647614938322, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81097649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40548809 + 40548810.

It is an arithmetic number, because the mean of its divisors is an integer number (40548810).

Almost surely, 2^81097619 is an apocalyptic number.

81097619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81097619 is an equidigital number, since it uses as much as digits as its factorization.

81097619 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 81097619 is about 9005.4216447649. The cubic root of 81097619 is about 432.8486173138.

The spelling of 81097619 in words is "eighty-one million, ninety-seven thousand, six hundred nineteen".