81449593 has 2 divisors, whose sum is σ = 81449594. Its totient is φ = 81449592.

The previous prime is 81449591. The next prime is 81449597. The reversal of 81449593 is 39594418.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75481344 + 5968249 = 8688^2 + 2443^2 .

It is a cyclic number.

It is not a de Polignac number, because 81449593 - 2¹ = 81449591 is a prime.

Together with 81449591, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81449591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40724796 + 40724797.

It is an arithmetic number, because the mean of its divisors is an integer number (40724797).

Almost surely, 2^81449593 is an apocalyptic number.

It is an amenable number.

81449593 is a deficient number, since it is larger than the sum of its proper divisors (1).

81449593 is an equidigital number, since it uses as much as digits as its factorization.

81449593 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 43.

The square root of 81449593 is about 9024.9428253037. The cubic root of 81449593 is about 433.4739196049.

The spelling of 81449593 in words is "eighty-one million, four hundred forty-nine thousand, five hundred ninety-three".