81345669120 has 672 divisors, whose sum is σ = 310336495560. Its totient is φ = 20384317440.

The previous prime is 81345669113. The next prime is 81345669173. The reversal of 81345669120 is 2196654318.

81345669120 is a `hidden beast` number, since 8 + 13 + 456 + 69 + 120 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 80801473536 + 544195584 = 284256^2 + 23328^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 126904000 + ... + 126904640.

Almost surely, 2^81345669120 is an apocalyptic number.

81345669120 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 81345669120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155168247780).

81345669120 is an abundant number, since it is smaller than the sum of its proper divisors (228990826440).

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

81345669120 is an equidigital number, since it uses as much as digits as its factorization.

81345669120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 703 (or 668 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 81345669120 in words is "eighty-one billion, three hundred forty-five million, six hundred sixty-nine thousand, one hundred twenty".