81543419 has 2 divisors, whose sum is σ = 81543420. Its totient is φ = 81543418.

The previous prime is 81543401. The next prime is 81543443. The reversal of 81543419 is 91434518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81543419 - 2²⁴ = 64766203 is a prime.

It is a super-2 number, since 2×81543419² = 13298658364419122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81543719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40771709 + 40771710.

It is an arithmetic number, because the mean of its divisors is an integer number (40771710).

Almost surely, 2^81543419 is an apocalyptic number.

81543419 is a deficient number, since it is larger than the sum of its proper divisors (1).

81543419 is an equidigital number, since it uses as much as digits as its factorization.

81543419 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 35.

The square root of 81543419 is about 9030.1394784355. The cubic root of 81543419 is about 433.6403027441.

The spelling of 81543419 in words is "eighty-one million, five hundred forty-three thousand, four hundred nineteen".