81009757 has 2 divisors, whose sum is σ = 81009758. Its totient is φ = 81009756.

The previous prime is 81009751. The next prime is 81009763. The reversal of 81009757 is 75790018.

It is a balanced prime because it is at equal distance from previous prime (81009751) and next prime (81009763).

It can be written as a sum of positive squares in only one way, i.e., 67716441 + 13293316 = 8229^2 + 3646^2 .

It is a cyclic number.

It is not a de Polignac number, because 81009757 - 2⁷ = 81009629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81009751) 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, 40504878 + 40504879.

It is an arithmetic number, because the mean of its divisors is an integer number (40504879).

Almost surely, 2^81009757 is an apocalyptic number.

It is an amenable number.

81009757 is a deficient number, since it is larger than the sum of its proper divisors (1).

81009757 is an equidigital number, since it uses as much as digits as its factorization.

81009757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17640, while the sum is 37.

The square root of 81009757 is about 9000.5420392330. The cubic root of 81009757 is about 432.6922432701.

The spelling of 81009757 in words is "eighty-one million, nine thousand, seven hundred fifty-seven".