81475680672 has 36 divisors (see below), whose sum is σ = 231696467730. Its totient is φ = 27158560128.

The previous prime is 81475680619. The next prime is 81475680673. The reversal of 81475680672 is 27608657418.

81475680672 is a `hidden beast` number, since 8 + 1 + 4 + 7 + 568 + 0 + 6 + 72 = 666.

It can be written as a sum of positive squares in only one way, i.e., 79774613136 + 1701067536 = 282444^2 + 41244^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (81475680673) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 141450547 + ... + 141451122.

Almost surely, 2^81475680672 is an apocalyptic number.

It is an amenable number.

81475680672 is an abundant number, since it is smaller than the sum of its proper divisors (150220787058).

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

81475680672 is a wasteful number, since it uses less digits than its factorization.

81475680672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282901685 (or 282901674 counting only the distinct ones).

The product of its (nonzero) digits is 4515840, while the sum is 54.

The spelling of 81475680672 in words is "eighty-one billion, four hundred seventy-five million, six hundred eighty thousand, six hundred seventy-two".