81919276992 has 224 divisors, whose sum is σ = 279342128640. Its totient is φ = 23055943680.

The previous prime is 81919276973. The next prime is 81919276993. The reversal of 81919276992 is 29967291918.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81919276993) 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 31 ways as a sum of consecutive naturals, for example, 759892 + ... + 860972.

Almost surely, 2^81919276992 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 81919276992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139671064320).

81919276992 is an abundant number, since it is smaller than the sum of its proper divisors (197422851648).

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

81919276992 is a wasteful number, since it uses less digits than its factorization.

81919276992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101176 (or 101160 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 63.

The spelling of 81919276992 in words is "eighty-one billion, nine hundred nineteen million, two hundred seventy-six thousand, nine hundred ninety-two".