81061549 has 2 divisors, whose sum is σ = 81061550. Its totient is φ = 81061548.

The previous prime is 81061531. The next prime is 81061553. The reversal of 81061549 is 94516018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54125449 + 26936100 = 7357^2 + 5190^2 .

It is a cyclic number.

It is not a de Polignac number, because 81061549 - 2⁵ = 81061517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81061529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40530774 + 40530775.

It is an arithmetic number, because the mean of its divisors is an integer number (40530775).

Almost surely, 2^81061549 is an apocalyptic number.

It is an amenable number.

81061549 is a deficient number, since it is larger than the sum of its proper divisors (1).

81061549 is an equidigital number, since it uses as much as digits as its factorization.

81061549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 81061549 is about 9003.4187395678. The cubic root of 81061549 is about 432.7844347270.

The spelling of 81061549 in words is "eighty-one million, sixty-one thousand, five hundred forty-nine".