81439948800 has 816 divisors, whose sum is σ = 343259220480. Its totient is φ = 18544066560.

The previous prime is 81439948783. The next prime is 81439948823. The reversal of 81439948800 is 884993418.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 309657469 + ... + 309657731.

Almost surely, 2^81439948800 is an apocalyptic number.

81439948800 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 81439948800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171629610240).

81439948800 is an abundant number, since it is smaller than the sum of its proper divisors (261819271680).

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

81439948800 is an equidigital number, since it uses as much as digits as its factorization.

81439948800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The spelling of 81439948800 in words is "eighty-one billion, four hundred thirty-nine million, nine hundred forty-eight thousand, eight hundred".