81784080 has 240 divisors, whose sum is σ = 326062464. Its totient is φ = 18662400.

The previous prime is 81784069. The next prime is 81784081. The reversal of 81784080 is 8048718.

It is a tau number, because it is divible by the number of its divisors (240).

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

It is not an unprimeable number, because it can be changed into a prime (81784081) 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, 135780 + ... + 136380.

Almost surely, 2^81784080 is an apocalyptic number.

81784080 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 81784080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163031232).

81784080 is an abundant number, since it is smaller than the sum of its proper divisors (244278384).

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

81784080 is a wasteful number, since it uses less digits than its factorization.

81784080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636 (or 618 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 81784080 is about 9043.4550919436. The cubic root of 81784080 is about 434.0664880050.

The spelling of 81784080 in words is "eighty-one million, seven hundred eighty-four thousand, eighty".