81646144197 has 8 divisors (see below), whose sum is σ = 112373187840. Its totient is φ = 52674931680.

The previous prime is 81646144187. The next prime is 81646144201. The reversal of 81646144197 is 79144164618.

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

It is not a de Polignac number, because 81646144197 - 2⁸ = 81646143941 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81646144147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 438957672 + ... + 438957857.

It is an arithmetic number, because the mean of its divisors is an integer number (14046648480).

Almost surely, 2^81646144197 is an apocalyptic number.

It is an amenable number.

81646144197 is a deficient number, since it is larger than the sum of its proper divisors (30727043643).

81646144197 is a wasteful number, since it uses less digits than its factorization.

81646144197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 877915563.

The product of its digits is 1161216, while the sum is 51.

The spelling of 81646144197 in words is "eighty-one billion, six hundred forty-six million, one hundred forty-four thousand, one hundred ninety-seven".