81655972447 has 8 divisors (see below), whose sum is σ = 94902825600. Its totient is φ = 68804547864.

The previous prime is 81655972417. The next prime is 81655972457. The reversal of 81655972447 is 74427955618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81655972447 - 2¹⁵ = 81655939679 is a prime.

It is a super-3 number, since 3×81655972447³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81655972391 and 81655972400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81655972417) 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, 98856697 + ... + 98857522.

It is an arithmetic number, because the mean of its divisors is an integer number (11862853200).

Almost surely, 2^81655972447 is an apocalyptic number.

81655972447 is a deficient number, since it is larger than the sum of its proper divisors (13246853153).

81655972447 is a wasteful number, since it uses less digits than its factorization.

81655972447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197714285.

The product of its digits is 16934400, while the sum is 58.

The spelling of 81655972447 in words is "eighty-one billion, six hundred fifty-five million, nine hundred seventy-two thousand, four hundred forty-seven".