81200128880 has 80 divisors (see below), whose sum is σ = 203390357184. Its totient is φ = 29970124800.

The previous prime is 81200128879. The next prime is 81200128903. The reversal of 81200128880 is 8882100218.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×81200128880² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2999405 + ... + 3026355.

Almost surely, 2^81200128880 is an apocalyptic number.

81200128880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81200128880 is an abundant number, since it is smaller than the sum of its proper divisors (122190228304).

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

81200128880 is a wasteful number, since it uses less digits than its factorization.

81200128880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29874 (or 29868 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 38.

The spelling of 81200128880 in words is "eighty-one billion, two hundred million, one hundred twenty-eight thousand, eight hundred eighty".