81495252473 has 2 divisors, whose sum is σ = 81495252474. Its totient is φ = 81495252472.

The previous prime is 81495252407. The next prime is 81495252479. The reversal of 81495252473 is 37425259418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43811513344 + 37683739129 = 209312^2 + 194123^2 .

It is a cyclic number.

It is not a de Polignac number, because 81495252473 - 2⁸ = 81495252217 is a prime.

It is a super-3 number, since 3×81495252473³ (a number of 34 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81495252479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40747626236 + 40747626237.

It is an arithmetic number, because the mean of its divisors is an integer number (40747626237).

Almost surely, 2^81495252473 is an apocalyptic number.

It is an amenable number.

81495252473 is a deficient number, since it is larger than the sum of its proper divisors (1).

81495252473 is an equidigital number, since it uses as much as digits as its factorization.

81495252473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 50.

The spelling of 81495252473 in words is "eighty-one billion, four hundred ninety-five million, two hundred fifty-two thousand, four hundred seventy-three".