81171767390 has 64 divisors (see below), whose sum is σ = 167479073280. Its totient is φ = 27747619200.

The previous prime is 81171767381. The next prime is 81171767401. The reversal of 81171767390 is 9376717118.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 54367484 + ... + 54368976.

It is an arithmetic number, because the mean of its divisors is an integer number (2616860520).

Almost surely, 2^81171767390 is an apocalyptic number.

81171767390 is an abundant number, since it is smaller than the sum of its proper divisors (86307305890).

81171767390 is a wasteful number, since it uses less digits than its factorization.

81171767390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3297.

The product of its (nonzero) digits is 444528, while the sum is 50.

The spelling of 81171767390 in words is "eighty-one billion, one hundred seventy-one million, seven hundred sixty-seven thousand, three hundred ninety".