81950492593 has 2 divisors, whose sum is σ = 81950492594. Its totient is φ = 81950492592.

The previous prime is 81950492567. The next prime is 81950492609. The reversal of 81950492593 is 39529405918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44136967744 + 37813524849 = 210088^2 + 194457^2 .

It is a cyclic number.

It is not a de Polignac number, because 81950492593 - 2⁹ = 81950492081 is a prime.

It is not a weakly prime, because it can be changed into another prime (81950492513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40975246296 + 40975246297.

It is an arithmetic number, because the mean of its divisors is an integer number (40975246297).

Almost surely, 2^81950492593 is an apocalyptic number.

It is an amenable number.

81950492593 is a deficient number, since it is larger than the sum of its proper divisors (1).

81950492593 is an equidigital number, since it uses as much as digits as its factorization.

81950492593 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3499200, while the sum is 55.

The spelling of 81950492593 in words is "eighty-one billion, nine hundred fifty million, four hundred ninety-two thousand, five hundred ninety-three".