81707448879 has 24 divisors (see below), whose sum is σ = 135092629152. Its totient is φ = 46617108480.

The previous prime is 81707448877. The next prime is 81707448913. The reversal of 81707448879 is 97884470718.

81707448879 is a `hidden beast` number, since 8 + 17 + 0 + 74 + 488 + 79 = 666.

It is not a de Polignac number, because 81707448879 - 2¹ = 81707448877 is a prime.

It is a super-2 number, since 2×81707448879² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81707448877) 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 23 ways as a sum of consecutive naturals, for example, 971274 + ... + 1052039.

It is an arithmetic number, because the mean of its divisors is an integer number (5628859548).

Almost surely, 2^81707448879 is an apocalyptic number.

81707448879 is a deficient number, since it is larger than the sum of its proper divisors (53385180273).

81707448879 is a wasteful number, since it uses less digits than its factorization.

81707448879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2023967 (or 2023964 counting only the distinct ones).

The product of its (nonzero) digits is 25288704, while the sum is 63.

The spelling of 81707448879 in words is "eighty-one billion, seven hundred seven million, four hundred forty-eight thousand, eight hundred seventy-nine".