81628785160 has 32 divisors (see below), whose sum is σ = 197792826840. Its totient is φ = 30139858944.

The previous prime is 81628785151. The next prime is 81628785187. The reversal of 81628785160 is 6158782618.

It can be written as a sum of positive squares in 4 ways, for example, as 70353318564 + 11275466596 = 265242^2 + 106186^2 .

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a junction number, because it is equal to n+sod(n) for n = 81628785098 and 81628785107.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78488697 + ... + 78489736.

Almost surely, 2^81628785160 is an apocalyptic number.

It is an amenable number.

81628785160 is an abundant number, since it is smaller than the sum of its proper divisors (116164041680).

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

81628785160 is a wasteful number, since it uses less digits than its factorization.

81628785160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156978457 (or 156978453 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 52.

The spelling of 81628785160 in words is "eighty-one billion, six hundred twenty-eight million, seven hundred eighty-five thousand, one hundred sixty".