81598393 has 2 divisors, whose sum is σ = 81598394. Its totient is φ = 81598392.

The previous prime is 81598339. The next prime is 81598409. The reversal of 81598393 is 39389518.

Together with previous prime (81598339) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64689849 + 16908544 = 8043^2 + 4112^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81598393 is a prime.

It is not a weakly prime, because it can be changed into another prime (81598313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40799196 + 40799197.

It is an arithmetic number, because the mean of its divisors is an integer number (40799197).

Almost surely, 2^81598393 is an apocalyptic number.

It is an amenable number.

81598393 is a deficient number, since it is larger than the sum of its proper divisors (1).

81598393 is an equidigital number, since it uses as much as digits as its factorization.

81598393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 46.

The square root of 81598393 is about 9033.1828831260. The cubic root of 81598393 is about 433.7377297229.

The spelling of 81598393 in words is "eighty-one million, five hundred ninety-eight thousand, three hundred ninety-three".