81019984 has 20 divisors (see below), whose sum is σ = 163802016. Its totient is φ = 38748512.

The previous prime is 81019979. The next prime is 81020003. The reversal of 81019984 is 48991018.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109714 + ... + 110449.

Almost surely, 2^81019984 is an apocalyptic number.

It is an amenable number.

81019984 is an abundant number, since it is smaller than the sum of its proper divisors (82782032).

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

81019984 is a wasteful number, since it uses less digits than its factorization.

81019984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220194 (or 220188 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 81019984 is about 9001.1101537533. The cubic root of 81019984 is about 432.7104507780.

The spelling of 81019984 in words is "eighty-one million, nineteen thousand, nine hundred eighty-four".