81413393 has 4 divisors (see below), whose sum is σ = 81769140. Its totient is φ = 81057648.

The previous prime is 81413377. The next prime is 81413407. The reversal of 81413393 is 39331418.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 71351809 + 10061584 = 8447^2 + 3172^2 .

It is a cyclic number.

It is not a de Polignac number, because 81413393 - 2⁴ = 81413377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81413303) 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 in 3 ways as a sum of consecutive naturals, for example, 177530 + ... + 177987.

It is an arithmetic number, because the mean of its divisors is an integer number (20442285).

Almost surely, 2^81413393 is an apocalyptic number.

It is an amenable number.

81413393 is a deficient number, since it is larger than the sum of its proper divisors (355747).

81413393 is a wasteful number, since it uses less digits than its factorization.

81413393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355746.

The product of its digits is 7776, while the sum is 32.

The square root of 81413393 is about 9022.9370495421. The cubic root of 81413393 is about 433.4096914093.

The spelling of 81413393 in words is "eighty-one million, four hundred thirteen thousand, three hundred ninety-three".