81339793 has 2 divisors, whose sum is σ = 81339794. Its totient is φ = 81339792.

The previous prime is 81339787. The next prime is 81339803. The reversal of 81339793 is 39793318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63632529 + 17707264 = 7977^2 + 4208^2 .

It is a cyclic number.

It is not a de Polignac number, because 81339793 - 2⁵ = 81339761 is a prime.

It is not a weakly prime, because it can be changed into another prime (81339733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40669896 + 40669897.

It is an arithmetic number, because the mean of its divisors is an integer number (40669897).

Almost surely, 2^81339793 is an apocalyptic number.

It is an amenable number.

81339793 is a deficient number, since it is larger than the sum of its proper divisors (1).

81339793 is an equidigital number, since it uses as much as digits as its factorization.

81339793 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 43.

The square root of 81339793 is about 9018.8576327604. The cubic root of 81339793 is about 433.2790471772.

The spelling of 81339793 in words is "eighty-one million, three hundred thirty-nine thousand, seven hundred ninety-three".