81015984 has 160 divisors (see below), whose sum is σ = 270141440. Its totient is φ = 22768128.

The previous prime is 81015929. The next prime is 81015997. The reversal of 81015984 is 48951018.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 220569 + ... + 220935.

It is an arithmetic number, because the mean of its divisors is an integer number (1688384).

Almost surely, 2^81015984 is an apocalyptic number.

81015984 is a gapful number since it is divisible by the number (84) 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 81015984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135070720).

81015984 is an abundant number, since it is smaller than the sum of its proper divisors (189125456).

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

81015984 is a wasteful number, since it uses less digits than its factorization.

81015984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 81015984 is about 9000.8879561963. The cubic root of 81015984 is about 432.7033296119.

The spelling of 81015984 in words is "eighty-one million, fifteen thousand, nine hundred eighty-four".