81905829947594 has 16 divisors (see below), whose sum is σ = 123145002856008. Its totient is φ = 40857499533312.

The previous prime is 81905829947593. The next prime is 81905829947597. The reversal of 81905829947594 is 49574992850918.

It can be written as a sum of positive squares in 4 ways, for example, as 80925407181025 + 980422766569 = 8995855^2 + 990163^2 .

It is a super-2 number, since 2×81905829947594² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81905829947593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42510824 + ... + 44395740.

Almost surely, 2^{81905829947594} is an apocalyptic number.

81905829947594 is a deficient number, since it is larger than the sum of its proper divisors (41239172908414).

81905829947594 is a wasteful number, since it uses less digits than its factorization.

81905829947594 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1935529.

The product of its (nonzero) digits is 2351462400, while the sum is 80.

The spelling of 81905829947594 in words is "eighty-one trillion, nine hundred five billion, eight hundred twenty-nine million, nine hundred forty-seven thousand, five hundred ninety-four".