81967680 has 224 divisors, whose sum is σ = 296265600. Its totient is φ = 21325824.

The previous prime is 81967649. The next prime is 81967723. The reversal of 81967680 is 8676918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 457831 + ... + 458009.

Almost surely, 2^81967680 is an apocalyptic number.

81967680 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 81967680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148132800).

81967680 is an abundant number, since it is smaller than the sum of its proper divisors (214297920).

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

81967680 is a wasteful number, since it uses less digits than its factorization.

81967680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 242 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 81967680 is about 9053.6003887956. The cubic root of 81967680 is about 434.3910623600.

It can be divided in two parts, 8196 and 7680, that added together give a square (15876 = 126²).

The spelling of 81967680 in words is "eighty-one million, nine hundred sixty-seven thousand, six hundred eighty".