81209437388800 has 1632 divisors, whose sum is σ = 255572092339200. Its totient is φ = 24970788864000.

The previous prime is 81209437388701. The next prime is 81209437388837. The reversal of 81209437388800 is 888373490218.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 448670924710 + ... + 448670924890.

Almost surely, 2^{81209437388800} is an apocalyptic number.

81209437388800 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 81209437388800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127786046169600).

81209437388800 is an abundant number, since it is smaller than the sum of its proper divisors (174362654950400).

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

81209437388800 is a wasteful number, since it uses less digits than its factorization.

81209437388800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 61.

The spelling of 81209437388800 in words is "eighty-one trillion, two hundred nine billion, four hundred thirty-seven million, three hundred eighty-eight thousand, eight hundred".