81908645486 has 8 divisors (see below), whose sum is σ = 125477074080. Its totient is φ = 40082954128.

The previous prime is 81908645471. The next prime is 81908645513. The reversal of 81908645486 is 68454680918.

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

It is a congruent number.

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, 435684191 + ... + 435684378.

It is an arithmetic number, because the mean of its divisors is an integer number (15684634260).

Almost surely, 2^81908645486 is an apocalyptic number.

81908645486 is a deficient number, since it is larger than the sum of its proper divisors (43568428594).

81908645486 is a wasteful number, since it uses less digits than its factorization.

81908645486 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 871368618.

The product of its (nonzero) digits is 13271040, while the sum is 59.

The spelling of 81908645486 in words is "eighty-one billion, nine hundred eight million, six hundred forty-five thousand, four hundred eighty-six".