81982368 has 144 divisors (see below), whose sum is σ = 260690976. Its totient is φ = 25194240.

The previous prime is 81982367. The next prime is 81982387. The reversal of 81982368 is 86328918.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×81982368² = 13442217325774848, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (81982367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100683 + ... + 101493.

It is an arithmetic number, because the mean of its divisors is an integer number (1810354).

Almost surely, 2^81982368 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 81982368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130345488).

81982368 is an abundant number, since it is smaller than the sum of its proper divisors (178708608).

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

81982368 is a wasteful number, since it uses less digits than its factorization.

81982368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 849 (or 829 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 81982368 is about 9054.4115214629. The cubic root of 81982368 is about 434.4170073620.

The spelling of 81982368 in words is "eighty-one million, nine hundred eighty-two thousand, three hundred sixty-eight".