81495619 has 2 divisors, whose sum is σ = 81495620. Its totient is φ = 81495618.

The previous prime is 81495613. The next prime is 81495643. The reversal of 81495619 is 91659418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81495619 - 2³ = 81495611 is a prime.

It is a super-2 number, since 2×81495619² = 13283071832386322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81495611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40747809 + 40747810.

It is an arithmetic number, because the mean of its divisors is an integer number (40747810).

Almost surely, 2^81495619 is an apocalyptic number.

81495619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81495619 is an equidigital number, since it uses as much as digits as its factorization.

81495619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 43.

The square root of 81495619 is about 9027.4923982244. The cubic root of 81495619 is about 433.5555542006. Note that the first 5 decimals are identical.

The spelling of 81495619 in words is "eighty-one million, four hundred ninety-five thousand, six hundred nineteen".