81339277 has 2 divisors, whose sum is σ = 81339278. Its totient is φ = 81339276.

The previous prime is 81339221. The next prime is 81339317. The reversal of 81339277 is 77293318.

It is an a-pointer prime, because the next prime (81339317) can be obtained adding 81339277 to its sum of digits (40).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68906601 + 12432676 = 8301^2 + 3526^2 .

It is a cyclic number.

It is not a de Polignac number, because 81339277 - 2⁷ = 81339149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81339217) 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, 40669638 + 40669639.

It is an arithmetic number, because the mean of its divisors is an integer number (40669639).

Almost surely, 2^81339277 is an apocalyptic number.

It is an amenable number.

81339277 is a deficient number, since it is larger than the sum of its proper divisors (1).

81339277 is an equidigital number, since it uses as much as digits as its factorization.

81339277 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504, while the sum is 40.

The square root of 81339277 is about 9018.8290259878. The cubic root of 81339277 is about 433.2781309694.

The spelling of 81339277 in words is "eighty-one million, three hundred thirty-nine thousand, two hundred seventy-seven".