81609253440000 has 3200 divisors, whose sum is σ = 341921393130240. Its totient is φ = 17187962880000.

The previous prime is 81609253439951. The next prime is 81609253440041. The reversal of 81609253440000 is 4435290618.

It is a tau number, because it is divible by the number of its divisors (3200).

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 4800544319992 + ... + 4800544320008.

Almost surely, 2^{81609253440000} is an apocalyptic number.

81609253440000 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 81609253440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170960696565120).

81609253440000 is an abundant number, since it is smaller than the sum of its proper divisors (260312139690240).

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

81609253440000 is an frugal number, since it uses more digits than its factorization.

81609253440000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 81609253440000 in words is "eighty-one trillion, six hundred nine billion, two hundred fifty-three million, four hundred forty thousand".