81709397362800 has 480 divisors, whose sum is σ = 299917913400000. Its totient is φ = 21115043020800.

The previous prime is 81709397362753. The next prime is 81709397362811. The reversal of 81709397362800 is 826379390718.

It is a congruent number.

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, 65357976 + ... + 66596424.

It is an arithmetic number, because the mean of its divisors is an integer number (624828986250).

Almost surely, 2^{81709397362800} is an apocalyptic number.

81709397362800 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 81709397362800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149958956700000).

81709397362800 is an abundant number, since it is smaller than the sum of its proper divisors (218208516037200).

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

81709397362800 is a wasteful number, since it uses less digits than its factorization.

81709397362800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1238666 (or 1238649 counting only the distinct ones).

The product of its (nonzero) digits is 27433728, while the sum is 63.

The spelling of 81709397362800 in words is "eighty-one trillion, seven hundred nine billion, three hundred ninety-seven million, three hundred sixty-two thousand, eight hundred".