81690831318 has 64 divisors (see below), whose sum is σ = 167967009792. Its totient is φ = 26474273280.

The previous prime is 81690831311. The next prime is 81690831329. The reversal of 81690831318 is 81313809618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81690831311) 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 31 ways as a sum of consecutive naturals, for example, 43614030 + ... + 43615902.

It is an arithmetic number, because the mean of its divisors is an integer number (2624484528).

Almost surely, 2^81690831318 is an apocalyptic number.

81690831318 is an abundant number, since it is smaller than the sum of its proper divisors (86276178474).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81690831318 is a wasteful number, since it uses less digits than its factorization.

81690831318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2869.

The product of its (nonzero) digits is 248832, while the sum is 48.

The spelling of 81690831318 in words is "eighty-one billion, six hundred ninety million, eight hundred thirty-one thousand, three hundred eighteen".