81545489 has 2 divisors, whose sum is σ = 81545490. Its totient is φ = 81545488.

The previous prime is 81545461. The next prime is 81545507. The reversal of 81545489 is 98454518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81450625 + 94864 = 9025^2 + 308^2 .

It is a cyclic number.

It is not a de Polignac number, because 81545489 - 2¹² = 81541393 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81595489) 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, 40772744 + 40772745.

It is an arithmetic number, because the mean of its divisors is an integer number (40772745).

Almost surely, 2^81545489 is an apocalyptic number.

It is an amenable number.

81545489 is a deficient number, since it is larger than the sum of its proper divisors (1).

81545489 is an equidigital number, since it uses as much as digits as its factorization.

81545489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 230400, while the sum is 44.

The square root of 81545489 is about 9030.2540938780. The cubic root of 81545489 is about 433.6439720688.

The spelling of 81545489 in words is "eighty-one million, five hundred forty-five thousand, four hundred eighty-nine".