81278801 has 2 divisors, whose sum is σ = 81278802. Its totient is φ = 81278800.

The previous prime is 81278777. The next prime is 81278831. The reversal of 81278801 is 10887218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80640400 + 638401 = 8980^2 + 799^2 .

It is a cyclic number.

It is not a de Polignac number, because 81278801 - 2¹⁸ = 81016657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81278831) 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, 40639400 + 40639401.

It is an arithmetic number, because the mean of its divisors is an integer number (40639401).

Almost surely, 2^81278801 is an apocalyptic number.

It is an amenable number.

81278801 is a deficient number, since it is larger than the sum of its proper divisors (1).

81278801 is an equidigital number, since it uses as much as digits as its factorization.

81278801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 81278801 is about 9015.4756391441. The cubic root of 81278801 is about 433.1707231426.

The spelling of 81278801 in words is "eighty-one million, two hundred seventy-eight thousand, eight hundred one".