81680276 has 6 divisors (see below), whose sum is σ = 142940490. Its totient is φ = 40840136.

The previous prime is 81680273. The next prime is 81680293. The reversal of 81680276 is 67208618.

It can be written as a sum of positive squares in only one way, i.e., 81468676 + 211600 = 9026^2 + 460^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81680273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210031 + ... + 10210038.

It is an arithmetic number, because the mean of its divisors is an integer number (23823415).

Almost surely, 2^81680276 is an apocalyptic number.

It is an amenable number.

81680276 is a deficient number, since it is larger than the sum of its proper divisors (61260214).

81680276 is a wasteful number, since it uses less digits than its factorization.

81680276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20420073 (or 20420071 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 81680276 is about 9037.7140915167. The cubic root of 81680276 is about 433.8827647412.

The spelling of 81680276 in words is "eighty-one million, six hundred eighty thousand, two hundred seventy-six".