81959040 has 384 divisors, whose sum is σ = 320785920. Its totient is φ = 19906560.

The previous prime is 81959029. The next prime is 81959047. The reversal of 81959040 is 4095918.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81958986 and 81959004.

It is not an unprimeable number, because it can be changed into a prime (81959047) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2643825 + ... + 2643855.

It is an arithmetic number, because the mean of its divisors is an integer number (835380).

Almost surely, 2^81959040 is an apocalyptic number.

81959040 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 81959040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160392960).

81959040 is an abundant number, since it is smaller than the sum of its proper divisors (238826880).

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

81959040 is a wasteful number, since it uses less digits than its factorization.

81959040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 81959040 is about 9053.1232179839. The cubic root of 81959040 is about 434.3757991463.

The spelling of 81959040 in words is "eighty-one million, nine hundred fifty-nine thousand, forty".