181649744640 has 1080 divisors, whose sum is σ = 804909032928. Its totient is φ = 38300221440.

The previous prime is 181649744621. The next prime is 181649744641. The reversal of 181649744640 is 46447946181.

181649744640 is a `hidden beast` number, since 18 + 1 + 64 + 97 + 446 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1080).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181649744641) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 122652700 + ... + 122654180.

Almost surely, 2^181649744640 is an apocalyptic number.

181649744640 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 181649744640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (402454516464).

181649744640 is an abundant number, since it is smaller than the sum of its proper divisors (623259288288).

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

181649744640 is a wasteful number, since it uses less digits than its factorization.

181649744640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547 (or 1511 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 54.

The spelling of 181649744640 in words is "one hundred eighty-one billion, six hundred forty-nine million, seven hundred forty-four thousand, six hundred forty".