81944667900 has 144 divisors (see below), whose sum is σ = 265995475200. Its totient is φ = 21639683520.

The previous prime is 81944667899. The next prime is 81944667907. The reversal of 81944667900 is 976644918.

81944667900 is a `hidden beast` number, since 8 + 1 + 94 + 466 + 7 + 90 + 0 = 666.

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 (81944667907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 130771 + ... + 425429.

It is an arithmetic number, because the mean of its divisors is an integer number (1847190800).

Almost surely, 2^81944667900 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81944667900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132997737600).

81944667900 is an abundant number, since it is smaller than the sum of its proper divisors (184050807300).

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

81944667900 is a wasteful number, since it uses less digits than its factorization.

81944667900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294785 (or 294772 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The spelling of 81944667900 in words is "eighty-one billion, nine hundred forty-four million, six hundred sixty-seven thousand, nine hundred".