81541724904 has 24 divisors (see below), whose sum is σ = 220842171810. Its totient is φ = 27180574944.

The previous prime is 81541724861. The next prime is 81541724917. The reversal of 81541724904 is 40942714518.

81541724904 is a `hidden beast` number, since 8 + 154 + 1 + 7 + 2 + 490 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 79101562500 + 2440162404 = 281250^2 + 49398^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×81541724904² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81541724904.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 566261907 + ... + 566262050.

Almost surely, 2^81541724904 is an apocalyptic number.

It is an amenable number.

81541724904 is an abundant number, since it is smaller than the sum of its proper divisors (139300446906).

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

81541724904 is a wasteful number, since it uses less digits than its factorization.

81541724904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132523969 (or 1132523962 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 81541724904 in words is "eighty-one billion, five hundred forty-one million, seven hundred twenty-four thousand, nine hundred four".