81906601804 has 12 divisors (see below), whose sum is σ = 143355157344. Its totient is φ = 40947985424.

The previous prime is 81906601781. The next prime is 81906601841. The reversal of 81906601804 is 40810660918.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1294099 + ... + 1355914.

It is an arithmetic number, because the mean of its divisors is an integer number (11946263112).

Almost surely, 2^81906601804 is an apocalyptic number.

It is an amenable number.

81906601804 is a deficient number, since it is larger than the sum of its proper divisors (61448555540).

81906601804 is a wasteful number, since it uses less digits than its factorization.

81906601804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2657744 (or 2657742 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The spelling of 81906601804 in words is "eighty-one billion, nine hundred six million, six hundred one thousand, eight hundred four".