81867867819 has 8 divisors (see below), whose sum is σ = 109164789312. Its totient is φ = 54574762440.

The previous prime is 81867867797. The next prime is 81867867833. The reversal of 81867867819 is 91876876818.

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

It is not a de Polignac number, because 81867867819 - 2⁸ = 81867867563 is a prime.

It is a super-2 number, since 2×81867867819² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81867867839) 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 7 ways as a sum of consecutive naturals, for example, 903589 + ... + 990054.

It is an arithmetic number, because the mean of its divisors is an integer number (13645598664).

Almost surely, 2^81867867819 is an apocalyptic number.

81867867819 is a deficient number, since it is larger than the sum of its proper divisors (27296921493).

81867867819 is a wasteful number, since it uses less digits than its factorization.

81867867819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1908057.

The product of its digits is 65028096, while the sum is 69.

The spelling of 81867867819 in words is "eighty-one billion, eight hundred sixty-seven million, eight hundred sixty-seven thousand, eight hundred nineteen".