81686813452 has 12 divisors (see below), whose sum is σ = 142954861840. Its totient is φ = 40842567216.

The previous prime is 81686813437. The next prime is 81686813489. The reversal of 81686813452 is 25431868618.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81686813452.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42874 + ... + 406462.

Almost surely, 2^81686813452 is an apocalyptic number.

It is an amenable number.

81686813452 is a deficient number, since it is larger than the sum of its proper divisors (61268048388).

81686813452 is a wasteful number, since it uses less digits than its factorization.

81686813452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419760 (or 419758 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 52.

The spelling of 81686813452 in words is "eighty-one billion, six hundred eighty-six million, eight hundred thirteen thousand, four hundred fifty-two".