81697338440964 has 27 divisors (see below), whose sum is σ = 206512853701063. Its totient is φ = 27232428069672.

The previous prime is 81697338440959. The next prime is 81697338440981. The reversal of 81697338440964 is 46904483379618.

It is a happy number.

The square root of 81697338440964 is 9038658.

It is a perfect power (a square), and thus also a powerful number.

81697338440964 is a `hidden beast` number, since 8 + 1 + 6 + 97 + 3 + 3 + 8 + 440 + 96 + 4 = 666.

It is a super-2 number, since 2×81697338440964² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81697338440892 and 81697338440901.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 53478727 + ... + 54985169.

Almost surely, 2^{81697338440964} is an apocalyptic number.

81697338440964 is the 9038658-th square number.

It is an amenable number.

81697338440964 is an abundant number, since it is smaller than the sum of its proper divisors (124815515260099).

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

81697338440964 is an frugal number, since it uses more digits than its factorization.

81697338440964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3012896 (or 1506448 counting only the distinct ones).

The product of its (nonzero) digits is 752467968, while the sum is 72.

The spelling of 81697338440964 in words is "eighty-one trillion, six hundred ninety-seven billion, three hundred thirty-eight million, four hundred forty thousand, nine hundred sixty-four".