81987900168 has 32 divisors (see below), whose sum is σ = 205540718400. Its totient is φ = 27253171008.

The previous prime is 81987900161. The next prime is 81987900209. The reversal of 81987900168 is 86100978918.

It is not an unprimeable number, because it can be changed into a prime (81987900161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4749271 + ... + 4766502.

It is an arithmetic number, because the mean of its divisors is an integer number (6423147450).

Almost surely, 2^81987900168 is an apocalyptic number.

It is an amenable number.

81987900168 is an abundant number, since it is smaller than the sum of its proper divisors (123552818232).

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

81987900168 is a wasteful number, since it uses less digits than its factorization.

81987900168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9516141 (or 9516137 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 57.

The spelling of 81987900168 in words is "eighty-one billion, nine hundred eighty-seven million, nine hundred thousand, one hundred sixty-eight".