81558793 has 2 divisors, whose sum is σ = 81558794. Its totient is φ = 81558792.

The previous prime is 81558749. The next prime is 81558797. The reversal of 81558793 is 39785518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42471289 + 39087504 = 6517^2 + 6252^2 .

It is a cyclic number.

It is not a de Polignac number, because 81558793 - 2¹⁷ = 81427721 is a prime.

It is not a weakly prime, because it can be changed into another prime (81558797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40779396 + 40779397.

It is an arithmetic number, because the mean of its divisors is an integer number (40779397).

Almost surely, 2^81558793 is an apocalyptic number.

It is an amenable number.

81558793 is a deficient number, since it is larger than the sum of its proper divisors (1).

81558793 is an equidigital number, since it uses as much as digits as its factorization.

81558793 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 46.

The square root of 81558793 is about 9030.9906986997. The cubic root of 81558793 is about 433.6675535313.

The spelling of 81558793 in words is "eighty-one million, five hundred fifty-eight thousand, seven hundred ninety-three".