81041773 has 2 divisors, whose sum is σ = 81041774. Its totient is φ = 81041772.

The previous prime is 81041767. The next prime is 81041777. The reversal of 81041773 is 37714018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74701449 + 6340324 = 8643^2 + 2518^2 .

It is a cyclic number.

It is not a de Polignac number, because 81041773 - 2¹³ = 81033581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81041777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40520886 + 40520887.

It is an arithmetic number, because the mean of its divisors is an integer number (40520887).

Almost surely, 2^81041773 is an apocalyptic number.

It is an amenable number.

81041773 is a deficient number, since it is larger than the sum of its proper divisors (1).

81041773 is an equidigital number, since it uses as much as digits as its factorization.

81041773 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 81041773 is about 9002.3204230909. The cubic root of 81041773 is about 432.7492374348.

The spelling of 81041773 in words is "eighty-one million, forty-one thousand, seven hundred seventy-three".