81904094209 has 16 divisors (see below), whose sum is σ = 95981178240. Its totient is φ = 68441506560.

The previous prime is 81904094201. The next prime is 81904094269. The reversal of 81904094209 is 90249040918.

It is not a de Polignac number, because 81904094209 - 2³ = 81904094201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81904094201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 800479 + ... + 896980.

It is an arithmetic number, because the mean of its divisors is an integer number (5998823640).

Almost surely, 2^81904094209 is an apocalyptic number.

It is an amenable number.

81904094209 is a deficient number, since it is larger than the sum of its proper divisors (14077084031).

81904094209 is a wasteful number, since it uses less digits than its factorization.

81904094209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697640.

The product of its (nonzero) digits is 186624, while the sum is 46.

The spelling of 81904094209 in words is "eighty-one billion, nine hundred four million, ninety-four thousand, two hundred nine".