81908645485 has 8 divisors (see below), whose sum is σ = 98384981760. Its totient is φ = 65463844944.

The previous prime is 81908645471. The next prime is 81908645513. The reversal of 81908645485 is 58454680918.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81908645485 - 2¹¹ = 81908643437 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7878217 + ... + 7888606.

It is an arithmetic number, because the mean of its divisors is an integer number (12298122720).

Almost surely, 2^81908645485 is an apocalyptic number.

It is an amenable number.

81908645485 is a deficient number, since it is larger than the sum of its proper divisors (16476336275).

81908645485 is a wasteful number, since it uses less digits than its factorization.

81908645485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15767867.

The product of its (nonzero) digits is 11059200, while the sum is 58.

The spelling of 81908645485 in words is "eighty-one billion, nine hundred eight million, six hundred forty-five thousand, four hundred eighty-five".