81381095040 has 256 divisors, whose sum is σ = 309350430720. Its totient is φ = 17792569344.

The previous prime is 81381095039. The next prime is 81381095041. The reversal of 81381095040 is 4059018318.

It is an interprime number because it is at equal distance from previous prime (81381095039) and next prime (81381095041).

It is a self number, because there is not a number n which added to its sum of digits gives 81381095040.

It is not an unprimeable number, because it can be changed into a prime (81381095041) 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, 177487 + ... + 440753.

It is an arithmetic number, because the mean of its divisors is an integer number (1208400120).

Almost surely, 2^81381095040 is an apocalyptic number.

81381095040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81381095040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154675215360).

81381095040 is an abundant number, since it is smaller than the sum of its proper divisors (227969335680).

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

81381095040 is a wasteful number, since it uses less digits than its factorization.

81381095040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263319 (or 263307 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The spelling of 81381095040 in words is "eighty-one billion, three hundred eighty-one million, ninety-five thousand, forty".