81553704728 has 16 divisors (see below), whose sum is σ = 152968781880. Its totient is φ = 40762029568.

The previous prime is 81553704721. The next prime is 81553704761. The reversal of 81553704728 is 82740735518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81553704721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1829450 + ... + 1873497.

Almost surely, 2^81553704728 is an apocalyptic number.

It is an amenable number.

81553704728 is a deficient number, since it is larger than the sum of its proper divisors (71415077152).

81553704728 is a wasteful number, since it uses less digits than its factorization.

81553704728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3705706 (or 3705702 counting only the distinct ones).

The product of its (nonzero) digits is 1881600, while the sum is 50.

The spelling of 81553704728 in words is "eighty-one billion, five hundred fifty-three million, seven hundred four thousand, seven hundred twenty-eight".