81505698 has 32 divisors (see below), whose sum is σ = 170781696. Its totient is φ = 25883088.

The previous prime is 81505607. The next prime is 81505717. The reversal of 81505698 is 89650518.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38011 + ... + 40097.

It is an arithmetic number, because the mean of its divisors is an integer number (5336928).

Almost surely, 2^81505698 is an apocalyptic number.

81505698 is an abundant number, since it is smaller than the sum of its proper divisors (89275998).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81505698 is a wasteful number, since it uses less digits than its factorization.

81505698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2398.

The product of its (nonzero) digits is 86400, while the sum is 42.

The square root of 81505698 is about 9028.0506201505. The cubic root of 81505698 is about 433.5734268436.

The spelling of 81505698 in words is "eighty-one million, five hundred five thousand, six hundred ninety-eight".