181385401680 has 320 divisors, whose sum is σ = 715754188800. Its totient is φ = 41359127040.

The previous prime is 181385401679. The next prime is 181385401693. The reversal of 181385401680 is 86104583181.

181385401680 is a `hidden beast` number, since 1 + 8 + 13 + 8 + 540 + 16 + 80 = 666.

It is a super-2 number, since 2×181385401680² (a number of 23 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6320965 + ... + 6349595.

It is an arithmetic number, because the mean of its divisors is an integer number (2236731840).

Almost surely, 2^181385401680 is an apocalyptic number.

181385401680 is a gapful number since it is divisible by the number (10) 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 181385401680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (357877094400).

181385401680 is an abundant number, since it is smaller than the sum of its proper divisors (534368787120).

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

181385401680 is a wasteful number, since it uses less digits than its factorization.

181385401680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29079 (or 29067 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 181385401680 in words is "one hundred eighty-one billion, three hundred eighty-five million, four hundred one thousand, six hundred eighty".