81528163772 has 24 divisors (see below), whose sum is σ = 163836503040. Its totient is φ = 35107821360.

The previous prime is 81528163757. The next prime is 81528163793. The reversal of 81528163772 is 27736182518.

It is a self number, because there is not a number n which added to its sum of digits gives 81528163772.

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, 48760028 + ... + 48761699.

It is an arithmetic number, because the mean of its divisors is an integer number (6826520960).

Almost surely, 2^81528163772 is an apocalyptic number.

It is an amenable number.

81528163772 is an abundant number, since it is smaller than the sum of its proper divisors (82308339268).

81528163772 is a wasteful number, since it uses less digits than its factorization.

81528163772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97521761 (or 97521759 counting only the distinct ones).

The product of its digits is 1128960, while the sum is 50.

The spelling of 81528163772 in words is "eighty-one billion, five hundred twenty-eight million, one hundred sixty-three thousand, seven hundred seventy-two".