81680888026 has 4 divisors (see below), whose sum is σ = 122521332042. Its totient is φ = 40840444012.

The previous prime is 81680887973. The next prime is 81680888027. The reversal of 81680888026 is 62088808618.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 80656568001 + 1024320025 = 284001^2 + 32005^2 .

It is not an unprimeable number, because it can be changed into a prime (81680888027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20420222005 + ... + 20420222008.

Almost surely, 2^81680888026 is an apocalyptic number.

81680888026 is a deficient number, since it is larger than the sum of its proper divisors (40840444016).

81680888026 is a wasteful number, since it uses less digits than its factorization.

81680888026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40840444015.

The product of its (nonzero) digits is 2359296, while the sum is 55.

The spelling of 81680888026 in words is "eighty-one billion, six hundred eighty million, eight hundred eighty-eight thousand, twenty-six".