81400850693 has 2 divisors, whose sum is σ = 81400850694. Its totient is φ = 81400850692.

The previous prime is 81400850669. The next prime is 81400850701. The reversal of 81400850693 is 39605800418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42126331009 + 39274519684 = 205247^2 + 198178^2 .

It is a cyclic number.

It is not a de Polignac number, because 81400850693 - 2²⁸ = 81132415237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81400850603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700425346 + 40700425347.

It is an arithmetic number, because the mean of its divisors is an integer number (40700425347).

Almost surely, 2^81400850693 is an apocalyptic number.

It is an amenable number.

81400850693 is a deficient number, since it is larger than the sum of its proper divisors (1).

81400850693 is an equidigital number, since it uses as much as digits as its factorization.

81400850693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 44.

The spelling of 81400850693 in words is "eighty-one billion, four hundred million, eight hundred fifty thousand, six hundred ninety-three".