81263549 has 2 divisors, whose sum is σ = 81263550. Its totient is φ = 81263548.

The previous prime is 81263521. The next prime is 81263561. The reversal of 81263549 is 94536218.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69139225 + 12124324 = 8315^2 + 3482^2 .

It is a cyclic number.

It is not a de Polignac number, because 81263549 - 2⁸ = 81263293 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 (81263569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40631774 + 40631775.

It is an arithmetic number, because the mean of its divisors is an integer number (40631775).

Almost surely, 2^81263549 is an apocalyptic number.

It is an amenable number.

81263549 is a deficient number, since it is larger than the sum of its proper divisors (1).

81263549 is an equidigital number, since it uses as much as digits as its factorization.

81263549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 38.

The square root of 81263549 is about 9014.6297206264. The cubic root of 81263549 is about 433.1436265603.

The spelling of 81263549 in words is "eighty-one million, two hundred sixty-three thousand, five hundred forty-nine".