81288547 has 2 divisors, whose sum is σ = 81288548. Its totient is φ = 81288546.

The previous prime is 81288511. The next prime is 81288553. The reversal of 81288547 is 74588218.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81288547 is a prime.

It is not a weakly prime, because it can be changed into another prime (81288847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40644273 + 40644274.

It is an arithmetic number, because the mean of its divisors is an integer number (40644274).

Almost surely, 2^81288547 is an apocalyptic number.

81288547 is a deficient number, since it is larger than the sum of its proper divisors (1).

81288547 is an equidigital number, since it uses as much as digits as its factorization.

81288547 is an evil number, because the sum of its binary digits is even.

The product of its digits is 143360, while the sum is 43.

The square root of 81288547 is about 9016.0161379625. The cubic root of 81288547 is about 433.1880360339.

The spelling of 81288547 in words is "eighty-one million, two hundred eighty-eight thousand, five hundred forty-seven".