81320999760 has 1680 divisors, whose sum is σ = 389356329600. Its totient is φ = 15519651840.

The previous prime is 81320999759. The next prime is 81320999777. The reversal of 81320999760 is 6799902318.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a super-2 number, since 2×81320999760² (a number of 23 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 81320999697 and 81320999706.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 408648141 + ... + 408648339.

It is an arithmetic number, because the mean of its divisors is an integer number (231759720).

Almost surely, 2^81320999760 is an apocalyptic number.

81320999760 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 81320999760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194678164800).

81320999760 is an abundant number, since it is smaller than the sum of its proper divisors (308035329840).

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

81320999760 is a wasteful number, since it uses less digits than its factorization.

81320999760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 1469664, while the sum is 54.

The spelling of 81320999760 in words is "eighty-one billion, three hundred twenty million, nine hundred ninety-nine thousand, seven hundred sixty".