81953567 has 2 divisors, whose sum is σ = 81953568. Its totient is φ = 81953566.

The previous prime is 81953551. The next prime is 81953587. The reversal of 81953567 is 76535918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81953567 - 2⁴ = 81953551 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81953587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40976783 + 40976784.

It is an arithmetic number, because the mean of its divisors is an integer number (40976784).

Almost surely, 2^81953567 is an apocalyptic number.

81953567 is a deficient number, since it is larger than the sum of its proper divisors (1).

81953567 is an equidigital number, since it uses as much as digits as its factorization.

81953567 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 44.

The square root of 81953567 is about 9052.8209415629. The cubic root of 81953567 is about 434.3661301227.

The spelling of 81953567 in words is "eighty-one million, nine hundred fifty-three thousand, five hundred sixty-seven".