81697649848 has 8 divisors (see below), whose sum is σ = 153183093480. Its totient is φ = 40848824920.

The previous prime is 81697649827. The next prime is 81697649849. The reversal of 81697649848 is 84894679618.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81697649849) 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 as a sum of consecutive naturals, namely, 5106103108 + ... + 5106103123.

It is an arithmetic number, because the mean of its divisors is an integer number (19147886685).

Almost surely, 2^81697649848 is an apocalyptic number.

It is an amenable number.

81697649848 is a deficient number, since it is larger than the sum of its proper divisors (71485443632).

81697649848 is a wasteful number, since it uses less digits than its factorization.

81697649848 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10212206237 (or 10212206233 counting only the distinct ones).

The product of its digits is 167215104, while the sum is 70.

The spelling of 81697649848 in words is "eighty-one billion, six hundred ninety-seven million, six hundred forty-nine thousand, eight hundred forty-eight".