81273761 has 2 divisors, whose sum is σ = 81273762. Its totient is φ = 81273760.

The previous prime is 81273737. The next prime is 81273799. The reversal of 81273761 is 16737218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49000000 + 32273761 = 7000^2 + 5681^2 .

It is a cyclic number.

It is not a de Polignac number, because 81273761 - 2¹⁸ = 81011617 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81273701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40636880 + 40636881.

It is an arithmetic number, because the mean of its divisors is an integer number (40636881).

Almost surely, 2^81273761 is an apocalyptic number.

It is an amenable number.

81273761 is a deficient number, since it is larger than the sum of its proper divisors (1).

81273761 is an equidigital number, since it uses as much as digits as its factorization.

81273761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 35.

The square root of 81273761 is about 9015.1961154486. The cubic root of 81273761 is about 433.1617694936.

The spelling of 81273761 in words is "eighty-one million, two hundred seventy-three thousand, seven hundred sixty-one".