81370730393 has 4 divisors (see below), whose sum is σ = 81660306228. Its totient is φ = 81081154560.

The previous prime is 81370730377. The next prime is 81370730407. The reversal of 81370730393 is 39303707318.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39303707318 = 2 ⋅19651853659.

It can be written as a sum of positive squares in 2 ways, for example, as 58674403984 + 22696326409 = 242228^2 + 150653^2 .

It is a cyclic number.

It is not a de Polignac number, because 81370730393 - 2⁴ = 81370730377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81372730393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144787496 + ... + 144788057.

It is an arithmetic number, because the mean of its divisors is an integer number (20415076557).

Almost surely, 2^81370730393 is an apocalyptic number.

It is an amenable number.

81370730393 is a deficient number, since it is larger than the sum of its proper divisors (289575835).

81370730393 is a wasteful number, since it uses less digits than its factorization.

81370730393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289575834.

The product of its (nonzero) digits is 285768, while the sum is 44.

The spelling of 81370730393 in words is "eighty-one billion, three hundred seventy million, seven hundred thirty thousand, three hundred ninety-three".