81904428288 has 72 divisors (see below), whose sum is σ = 242205824000. Its totient is φ = 27301473792.

The previous prime is 81904428283. The next prime is 81904428301. The reversal of 81904428288 is 88282440918.

81904428288 is a `hidden beast` number, since 8 + 190 + 4 + 428 + 28 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×81904428288² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81904428283) by changing a digit.

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, 5917888 + ... + 5931711.

Almost surely, 2^81904428288 is an apocalyptic number.

It is an amenable number.

81904428288 is an abundant number, since it is smaller than the sum of its proper divisors (160301395712).

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

81904428288 is a wasteful number, since it uses less digits than its factorization.

81904428288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11849624 (or 11849604 counting only the distinct ones).

The product of its (nonzero) digits is 2359296, while the sum is 54.

The spelling of 81904428288 in words is "eighty-one billion, nine hundred four million, four hundred twenty-eight thousand, two hundred eighty-eight".