81697649913 has 12 divisors (see below), whose sum is σ = 128735690928. Its totient is φ = 49513727160.

The previous prime is 81697649899. The next prime is 81697649927. The reversal of 81697649913 is 31994679618.

81697649913 is a `hidden beast` number, since 8 + 1 + 69 + 76 + 499 + 13 = 666.

It is an interprime number because it is at equal distance from previous prime (81697649899) and next prime (81697649927).

It is not a de Polignac number, because 81697649913 - 2⁶ = 81697649849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81697649963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 412614295 + ... + 412614492.

It is an arithmetic number, because the mean of its divisors is an integer number (10727974244).

Almost surely, 2^81697649913 is an apocalyptic number.

It is an amenable number.

81697649913 is a deficient number, since it is larger than the sum of its proper divisors (47038041015).

81697649913 is a wasteful number, since it uses less digits than its factorization.

81697649913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825228804 (or 825228801 counting only the distinct ones).

The product of its digits is 17635968, while the sum is 63.

The spelling of 81697649913 in words is "eighty-one billion, six hundred ninety-seven million, six hundred forty-nine thousand, nine hundred thirteen".