81371878800 has 240 divisors, whose sum is σ = 266272957440. Its totient is φ = 21236544000.

The previous prime is 81371878799. The next prime is 81371878801. The reversal of 81371878800 is 887817318.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81371878799) and next prime (81371878801).

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (81371878801) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11839365 + ... + 11846235.

It is an arithmetic number, because the mean of its divisors is an integer number (1109470656).

Almost surely, 2^81371878800 is an apocalyptic number.

81371878800 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 81371878800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133136478720).

81371878800 is an abundant number, since it is smaller than the sum of its proper divisors (184901078640).

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

81371878800 is a wasteful number, since it uses less digits than its factorization.

81371878800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7102 (or 7091 counting only the distinct ones).

The product of its (nonzero) digits is 602112, while the sum is 51.

The spelling of 81371878800 in words is "eighty-one billion, three hundred seventy-one million, eight hundred seventy-eight thousand, eight hundred".