81341680 has 40 divisors (see below), whose sum is σ = 216137952. Its totient is φ = 27888384.

The previous prime is 81341671. The next prime is 81341683. The reversal of 81341680 is 8614318.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81341683) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 72067 + ... + 73186.

Almost surely, 2^81341680 is an apocalyptic number.

81341680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81341680 is an abundant number, since it is smaller than the sum of its proper divisors (134796272).

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

81341680 is a wasteful number, since it uses less digits than its factorization.

81341680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145273 (or 145267 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 81341680 is about 9018.9622462898. The cubic root of 81341680 is about 433.2823976949.

Adding to 81341680 its reverse (8614318), we get a palindrome (89955998).

The spelling of 81341680 in words is "eighty-one million, three hundred forty-one thousand, six hundred eighty".