81042656186 has 4 divisors (see below), whose sum is σ = 121563984282. Its totient is φ = 40521328092.

The previous prime is 81042656147. The next prime is 81042656203. The reversal of 81042656186 is 68165624018.

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., 54950392225 + 26092263961 = 234415^2 + 161531^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81042656186.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20260664045 + ... + 20260664048.

Almost surely, 2^81042656186 is an apocalyptic number.

81042656186 is a deficient number, since it is larger than the sum of its proper divisors (40521328096).

81042656186 is a wasteful number, since it uses less digits than its factorization.

81042656186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40521328095.

The product of its (nonzero) digits is 552960, while the sum is 47.

The spelling of 81042656186 in words is "eighty-one billion, forty-two million, six hundred fifty-six thousand, one hundred eighty-six".