181730640 has 320 divisors, whose sum is σ = 710954496. Its totient is φ = 37380096.

The previous prime is 181730621. The next prime is 181730657. The reversal of 181730640 is 46037181.

181730640 = T₃₂₀₅ + T₃₂₀₆ + ... + T₃₂₃₉.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 181730598 and 181730607.

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, 1157442 + ... + 1157598.

Almost surely, 2^181730640 is an apocalyptic number.

181730640 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 181730640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355477248).

181730640 is an abundant number, since it is smaller than the sum of its proper divisors (529223856).

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

181730640 is a wasteful number, since it uses less digits than its factorization.

181730640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 181730640 is about 13480.7507209354. The cubic root of 181730640 is about 566.4253982514.

The spelling of 181730640 in words is "one hundred eighty-one million, seven hundred thirty thousand, six hundred forty".