81455047 has 2 divisors, whose sum is σ = 81455048. Its totient is φ = 81455046.

The previous prime is 81455021. The next prime is 81455057. The reversal of 81455047 is 74055418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81455047 - 2²³ = 73066439 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81455057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40727523 + 40727524.

It is an arithmetic number, because the mean of its divisors is an integer number (40727524).

Almost surely, 2^81455047 is an apocalyptic number.

81455047 is a deficient number, since it is larger than the sum of its proper divisors (1).

81455047 is an equidigital number, since it uses as much as digits as its factorization.

81455047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22400, while the sum is 34.

The square root of 81455047 is about 9025.2449828246. The cubic root of 81455047 is about 433.4835947668.

The spelling of 81455047 in words is "eighty-one million, four hundred fifty-five thousand, forty-seven".