81297487 has 2 divisors, whose sum is σ = 81297488. Its totient is φ = 81297486.

The previous prime is 81297481. The next prime is 81297493. The reversal of 81297487 is 78479218.

It is a balanced prime because it is at equal distance from previous prime (81297481) and next prime (81297493).

It is a cyclic number.

It is not a de Polignac number, because 81297487 - 2²³ = 72908879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81297481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40648743 + 40648744.

It is an arithmetic number, because the mean of its divisors is an integer number (40648744).

Almost surely, 2^81297487 is an apocalyptic number.

81297487 is a deficient number, since it is larger than the sum of its proper divisors (1).

81297487 is an equidigital number, since it uses as much as digits as its factorization.

81297487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 46.

The square root of 81297487 is about 9016.5119087150. The cubic root of 81297487 is about 433.2039159220.

The spelling of 81297487 in words is "eighty-one million, two hundred ninety-seven thousand, four hundred eighty-seven".