81641653658867 has 8 divisors (see below), whose sum is σ = 81693547740000. Its totient is φ = 81589761013824.

The previous prime is 81641653658849. The next prime is 81641653658909. The reversal of 81641653658867 is 76885635614618.

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 81641653658867 - 2²² = 81641649464563 is a prime.

It is a super-2 number, since 2×81641653658867² (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 = 81641653658794 and 81641653658803.

It is not an unprimeable number, because it can be changed into a prime (81641653658167) 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, 127898009 + ... + 128534757.

It is an arithmetic number, because the mean of its divisors is an integer number (10211693467500).

Almost surely, 2^{81641653658867} is an apocalyptic number.

81641653658867 is a deficient number, since it is larger than the sum of its proper divisors (51894081133).

81641653658867 is a wasteful number, since it uses less digits than its factorization.

81641653658867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718045.

The product of its digits is 1393459200, while the sum is 74.

The spelling of 81641653658867 in words is "eighty-one trillion, six hundred forty-one billion, six hundred fifty-three million, six hundred fifty-eight thousand, eight hundred sixty-seven".