81461317392 has 480 divisors, whose sum is σ = 292105748480. Its totient is φ = 20614487040.

The previous prime is 81461317351. The next prime is 81461317409. The reversal of 81461317392 is 29371316418.

81461317392 is a `hidden beast` number, since 8 + 1 + 461 + 31 + 73 + 92 = 666.

It is a nude number because it is divisible by every one of its digits.

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 95 ways as a sum of consecutive naturals, for example, 51589659 + ... + 51591237.

Almost surely, 2^81461317392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81461317392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146052874240).

81461317392 is an abundant number, since it is smaller than the sum of its proper divisors (210644431088).

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

81461317392 is a wasteful number, since it uses less digits than its factorization.

81461317392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1771 (or 1762 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The spelling of 81461317392 in words is "eighty-one billion, four hundred sixty-one million, three hundred seventeen thousand, three hundred ninety-two".