81271040692564 has 6 divisors (see below), whose sum is σ = 142224321211994. Its totient is φ = 40635520346280.

The previous prime is 81271040692547. The next prime is 81271040692573. The reversal of 81271040692564 is 46529604017218.

It can be written as a sum of positive squares in only one way, i.e., 67915597352464 + 13355443340100 = 8241092^2 + 3654510^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10158880086567 + ... + 10158880086574.

Almost surely, 2^{81271040692564} is an apocalyptic number.

It is an amenable number.

81271040692564 is a deficient number, since it is larger than the sum of its proper divisors (60953280519430).

81271040692564 is a wasteful number, since it uses less digits than its factorization.

81271040692564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20317760173145 (or 20317760173143 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 55.

The spelling of 81271040692564 in words is "eighty-one trillion, two hundred seventy-one billion, forty million, six hundred ninety-two thousand, five hundred sixty-four".