81571962549696 has 56 divisors (see below), whose sum is σ = 217274313075600. Its totient is φ = 27008166561792.

The previous prime is 81571962549691. The next prime is 81571962549811. The reversal of 81571962549696 is 69694526917518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81571962549691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1425655861 + ... + 1425713076.

Almost surely, 2^{81571962549696} is an apocalyptic number.

It is an amenable number.

81571962549696 is an abundant number, since it is smaller than the sum of its proper divisors (135702350525904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81571962549696 is a wasteful number, since it uses less digits than its factorization.

81571962549696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2851369101 (or 2851369091 counting only the distinct ones).

The product of its digits is 1763596800, while the sum is 78.

The spelling of 81571962549696 in words is "eighty-one trillion, five hundred seventy-one billion, nine hundred sixty-two million, five hundred forty-nine thousand, six hundred ninety-six".