81940859353 has 2 divisors, whose sum is σ = 81940859354. Its totient is φ = 81940859352.

The previous prime is 81940859281. The next prime is 81940859387. The reversal of 81940859353 is 35395804918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81529094089 + 411765264 = 285533^2 + 20292^2 .

It is a cyclic number.

It is not a de Polignac number, because 81940859353 - 2³³ = 73350924761 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81940859294 and 81940859303.

It is not a weakly prime, because it can be changed into another prime (81940859393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40970429676 + 40970429677.

It is an arithmetic number, because the mean of its divisors is an integer number (40970429677).

Almost surely, 2^81940859353 is an apocalyptic number.

It is an amenable number.

81940859353 is a deficient number, since it is larger than the sum of its proper divisors (1).

81940859353 is an equidigital number, since it uses as much as digits as its factorization.

81940859353 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4665600, while the sum is 55.

The spelling of 81940859353 in words is "eighty-one billion, nine hundred forty million, eight hundred fifty-nine thousand, three hundred fifty-three".