81359647 has 2 divisors, whose sum is σ = 81359648. Its totient is φ = 81359646.

The previous prime is 81359627. The next prime is 81359659. The reversal of 81359647 is 74695318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81359647 - 2⁷ = 81359519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81359627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40679823 + 40679824.

It is an arithmetic number, because the mean of its divisors is an integer number (40679824).

Almost surely, 2^81359647 is an apocalyptic number.

81359647 is a deficient number, since it is larger than the sum of its proper divisors (1).

81359647 is an equidigital number, since it uses as much as digits as its factorization.

81359647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 43.

The square root of 81359647 is about 9019.9582593269. The cubic root of 81359647 is about 433.3142969284.

The spelling of 81359647 in words is "eighty-one million, three hundred fifty-nine thousand, six hundred forty-seven".