81039149680 has 80 divisors (see below), whose sum is σ = 193373676864. Its totient is φ = 31571671040.

The previous prime is 81039149603. The next prime is 81039149713. The reversal of 81039149680 is 8694193018.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 511125 + ... + 650635.

Almost surely, 2^81039149680 is an apocalyptic number.

81039149680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81039149680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96686838432).

81039149680 is an abundant number, since it is smaller than the sum of its proper divisors (112334527184).

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

81039149680 is a wasteful number, since it uses less digits than its factorization.

81039149680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139714 (or 139708 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 49.

The spelling of 81039149680 in words is "eighty-one billion, thirty-nine million, one hundred forty-nine thousand, six hundred eighty".