81877158720 has 672 divisors, whose sum is σ = 335504332800. Its totient is φ = 18618107904.

The previous prime is 81877158661. The next prime is 81877158731. The reversal of 81877158720 is 2785177818.

It is a tau number, because it is divible by the number of its divisors (672).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 195410671 + ... + 195411089.

It is an arithmetic number, because the mean of its divisors is an integer number (499262400).

Almost surely, 2^81877158720 is an apocalyptic number.

81877158720 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 81877158720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (167752166400).

81877158720 is an abundant number, since it is smaller than the sum of its proper divisors (253627174080).

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

81877158720 is a wasteful number, since it uses less digits than its factorization.

81877158720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817 (or 795 counting only the distinct ones).

The product of its (nonzero) digits is 1756160, while the sum is 54.

The spelling of 81877158720 in words is "eighty-one billion, eight hundred seventy-seven million, one hundred fifty-eight thousand, seven hundred twenty".