81892640786 has 8 divisors (see below), whose sum is σ = 134006139504. Its totient is φ = 37223927620.

The previous prime is 81892640783. The next prime is 81892640827. The reversal of 81892640786 is 68704629818.

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

It is a super-2 number, since 2×81892640786² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81892640783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1861196360 + ... + 1861196403.

It is an arithmetic number, because the mean of its divisors is an integer number (16750767438).

Almost surely, 2^81892640786 is an apocalyptic number.

81892640786 is a deficient number, since it is larger than the sum of its proper divisors (52113498718).

81892640786 is a wasteful number, since it uses less digits than its factorization.

81892640786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3722392776.

The product of its (nonzero) digits is 9289728, while the sum is 59.

The spelling of 81892640786 in words is "eighty-one billion, eight hundred ninety-two million, six hundred forty thousand, seven hundred eighty-six".