81960172800 has 324 divisors, whose sum is σ = 297319095360. Its totient is φ = 19868569600.

The previous prime is 81960172793. The next prime is 81960172807. The reversal of 81960172800 is 827106918.

It is an interprime number because it is at equal distance from previous prime (81960172793) and next prime (81960172807).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81960172807) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2305561 + ... + 2340839.

Almost surely, 2^81960172800 is an apocalyptic number.

81960172800 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 81960172800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148659547680).

81960172800 is an abundant number, since it is smaller than the sum of its proper divisors (215358922560).

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

81960172800 is a wasteful number, since it uses less digits than its factorization.

81960172800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35330 (or 35300 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The spelling of 81960172800 in words is "eighty-one billion, nine hundred sixty million, one hundred seventy-two thousand, eight hundred".