81641419 has 2 divisors, whose sum is σ = 81641420. Its totient is φ = 81641418.

The previous prime is 81641387. The next prime is 81641489. The reversal of 81641419 is 91414618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81641419 - 2⁵ = 81641387 is a prime.

It is a super-2 number, since 2×81641419² = 13330642592667122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81641489) 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, 40820709 + 40820710.

It is an arithmetic number, because the mean of its divisors is an integer number (40820710).

Almost surely, 2^81641419 is an apocalyptic number.

81641419 is a deficient number, since it is larger than the sum of its proper divisors (1).

81641419 is an equidigital number, since it uses as much as digits as its factorization.

81641419 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 34.

The square root of 81641419 is about 9035.5641218465. The cubic root of 81641419 is about 433.8139514872.

The spelling of 81641419 in words is "eighty-one million, six hundred forty-one thousand, four hundred nineteen".