81125909756 has 36 divisors (see below), whose sum is σ = 154621139400. Its totient is φ = 37096841376.

The previous prime is 81125909749. The next prime is 81125909791. The reversal of 81125909756 is 65790952118.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81125909698 and 81125909707.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13368635 + ... + 13374701.

It is an arithmetic number, because the mean of its divisors is an integer number (4295031650).

Almost surely, 2^81125909756 is an apocalyptic number.

It is an amenable number.

81125909756 is a deficient number, since it is larger than the sum of its proper divisors (73495229644).

81125909756 is an equidigital number, since it uses as much as digits as its factorization.

81125909756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12186 (or 6117 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 53.

The spelling of 81125909756 in words is "eighty-one billion, one hundred twenty-five million, nine hundred nine thousand, seven hundred fifty-six".