81398893 has 2 divisors, whose sum is σ = 81398894. Its totient is φ = 81398892.

The previous prime is 81398881. The next prime is 81398923. The reversal of 81398893 is 39889318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54493924 + 26904969 = 7382^2 + 5187^2 .

It is a cyclic number.

It is not a de Polignac number, because 81398893 - 2²¹ = 79301741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81398803) 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, 40699446 + 40699447.

It is an arithmetic number, because the mean of its divisors is an integer number (40699447).

Almost surely, 2^81398893 is an apocalyptic number.

It is an amenable number.

81398893 is a deficient number, since it is larger than the sum of its proper divisors (1).

81398893 is an equidigital number, since it uses as much as digits as its factorization.

81398893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 373248, while the sum is 49.

The square root of 81398893 is about 9022.1335059951. The cubic root of 81398893 is about 433.3839593054.

The spelling of 81398893 in words is "eighty-one million, three hundred ninety-eight thousand, eight hundred ninety-three".