71821680 has 80 divisors (see below), whose sum is σ = 254459904. Its totient is φ = 16416000.

The previous prime is 71821679. The next prime is 71821693. The reversal of 71821680 is 8612817.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 19696 + ... + 23055.

Almost surely, 2^71821680 is an apocalyptic number.

71821680 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

71821680 is an abundant number, since it is smaller than the sum of its proper divisors (182638224).

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

71821680 is a wasteful number, since it uses less digits than its factorization.

71821680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42774 (or 42768 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 71821680 is about 8474.7672534412. The cubic root of 71821680 is about 415.6730357355.

The spelling of 71821680 in words is "seventy-one million, eight hundred twenty-one thousand, six hundred eighty".