81354913 has 2 divisors, whose sum is σ = 81354914. Its totient is φ = 81354912.

The previous prime is 81354901. The next prime is 81354919. The reversal of 81354913 is 31945318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80138304 + 1216609 = 8952^2 + 1103^2 .

It is a cyclic number.

It is not a de Polignac number, because 81354913 - 2¹³ = 81346721 is a prime.

It is not a weakly prime, because it can be changed into another prime (81354919) 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, 40677456 + 40677457.

It is an arithmetic number, because the mean of its divisors is an integer number (40677457).

Almost surely, 2^81354913 is an apocalyptic number.

It is an amenable number.

81354913 is a deficient number, since it is larger than the sum of its proper divisors (1).

81354913 is an equidigital number, since it uses as much as digits as its factorization.

81354913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 81354913 is about 9019.6958374437. The cubic root of 81354913 is about 433.3058924767.

The spelling of 81354913 in words is "eighty-one million, three hundred fifty-four thousand, nine hundred thirteen".